Democrats in Congress are escalating their war against President Trump, with an eye to finding some grounds to impeach the President prior to the 2020 elections. The New York Times frames their case in a news story in the May 9 edition of the newspaper:

House Democrats, infuriated by President Trump’s stonewalling, are struggling to mount a more aggressive campaign to compel him to cooperate with their investigations—a push that could include a threat to jail officials, garnish their wages and perhaps even impeach the President. With Mr. Trump throwing up roadblocks on practically a daily basis, Democrats and their leaders are feeling new urgency to assert their power as a coequal branch of government.

In mounting this campaign against the President, Democrats have been egged on by their more ideological members, their activist base, an army of Twitter commentators, and editorialists and opinion writers at several prominent newspapers, including The New York Times. They are to a person convinced that the President is a bad man, that he was elected in 2016 by underhanded means, and that, therefore, he must be guilty of crimes deserving impeachment and removal from office. They had bet heavily on Robert Mueller’s investigation but after two years of sound and fury he was not able to pin anything on the President. With the clock running down to next year’s election, Democrats face the challenge of coming up with something very soon to justify impeaching the President.

Democrats and their loud supporters outside Congress seem shocked that the President should be throwing up roadblocks in their campaign to remove him from office. But if Mr. Trump is as ruthless as they claim him to be, then it should be expected that he will fight back with all the tools at his disposal—which is exactly what he is going to do, much to the delight of his own substantial army of supporters. As it turns out, the President has many such tools to blunt the march to impeachment—enough of them, in fact, to extend the controversy well into next year, when it will become a polarizing issue in the 2020 elections.

Like much else in the Constitution, impeachment is a mixture of political and legal considerations. In Federalist 65, Alexander Hamilton discusses impeachment in terms of “the judicial character of the Senate.” He proceeds then to write that impeachments are “political” in nature “as they relate chiefly to injuries done immediately to society itself.” This is the reason that the sole power of impeachment is given to the political branch—the House of Representatives and the Senate—rather than to the courts. Hamilton recognizes that impeachments “will seldom fail to agitate the passions of the whole community, and divide it into parties more or less friendly or inimical to the accused.” Nevertheless, the Constitution describes impeachment in legal terms involving “treason, bribery, or other high crimes and misdemeanors.” Such terms have precise meanings in courts of law, and in fact were derived by the authors of the Constitution from English common law, but at the same time are far less clear when examined in a political context. In high-profile impeachment cases, legal and constitutional claims are usually grounded in political calculations of one kind or another. In the end, impeachment of presidents is mostly a political process, which is why it will always be attended to by “roadblocks” of the kind the founders deliberately inserted into the Constitution.

In the present case, the Democrats fired the first shot when the House Judiciary Committee issued a subpoena to Attorney General William Barr demanding that he produce a full and unredacted copy of the Mueller Report, even though close to 90 percent of that report has already been delivered to the Congress and the public. The Attorney General has so far defied the subpoena, claiming that the controlling law does not permit the public release of confidential sections of the report. The House Committee on Ways and Means is also likely to issue a subpoena to the Secretary of the Treasury to produce copies of the President’s tax returns, in the hope that those documents will yield information embarrassing to the President and perhaps a few violations justifying impeachment. Thus far Secretary Mnuchin has defied those requests as well, and will certainly defy any subpoena if and when it is issued. Quite independently of all this, though obviously related to it, President Trump has sued Duetsche Bank and Capital One to enjoin those financial companies from complying with yet another congressional subpoena demanding release of his private business records.

What happens next is anyone’s guess. If President Trump decides that it is in his interest to stymie the Democrats and escalate the war, then he will continue to defy the subpoenas. Possibly more of them will be issued in the weeks to come. Some have suggested that the House could order the arrest of the Attorney General and Secretary of the Treasury, and any other member of the executive branch for that matter, for defying the subpoenas. That would be an extreme step and a highly unlikely one, unless the Speaker of the House is prepared to send her Sergeant at Arms to arrest the Attorney General for contempt of Congress, thereby risking a fist fight or a shoot-out at the Department of Justice with the U.S. Marshalls assigned to protect him. That would be an unprecedented spectacle, though perhaps reminiscent of the occasion in 1856 when Rep. Preston Brooks of South Carolina went into the Senate chamber to beat Sen. Charles Sumner within an inch of his life (an event that signaled greater violence to come).

It is far more likely that the House will go into federal district court in Washington to request a court order to enforce the subpoena(s). The President will challenge those subpoenas in the hearings. A judge will eventually render a decision favoring one or the other party, though it may take many weeks or even months for that to happen, with the administration deploying every delaying tactic at its disposal. The losing party will appeal to the D.C. Circuit Court of Appeals in a second stage of arguments that will also take weeks or months before it is concluded. The loser will again appeal the result to the United State Supreme Court, whereupon arguments will be scheduled and briefs submitted for review in anticipation of a final ruling. How long will this process take? It is possible, given the typical pace of such lawsuits, that it could extend well into 2020—a timetable advantageous the President, who will be content to “run out the clock” until November 2020. That likely timetable also applies to the lawsuits over the President’s income tax and financial records.

It is impossible to tell how the courts will eventually decide these cases. Many Democrats, citing precedents from the Nixon impeachment, claim that the federal courts will eventually rule in favor of Congress, thereby recognizing its investigative and oversight powers under the Constitution. Yet the parallels with the Nixon case are far from exact. In that case, the Supreme Court ordered President Nixon to turn over his private tapes to the independent counsel (not to Congress) because the tapes were judged to be evidence in a criminal trial then before a court. There is no underlying crime in the present case for which the unredacted Mueller Report (or the President’s tax returns) could be cited as evidence. There is the Roger Stone indictment, but in that case the report (if requested) would be delivered to the relevant court rather than to Congress.

Democrats in the House want to use those documents to identify crimes, not as evidence of crimes already on the record. In addition, the Independent Counsel in 1973 and 1974 worked outside the Justice Department, while the Special Counsel today (under the current statute) operates under the guidance of the Attorney General, who preserves legal discretion as to how documents may be used. Attorney General Barr, for his part, maintains that the controlling statue enjoins him from releasing to the public or to Congress grand jury information contained in the Mueller Report. In short, the precedents from the Nixon impeachment are not on Congress’s side in the current situation.

If the Supreme Court eventually rules in favor of President Trump, then the game is probably up insofar as impeachment is concerned, because such an outcome would deprive Democrats of potential evidence that might provide grounds for impeachment. It would also foreclose a back-up tactic now being considered—that is, to pass a resolution of impeachment based upon the President’s defiance of congressional subpoenas and his obstruction of legitimate congressional inquiries. This was one of the charges advanced by the Judiciary Committee in the Nixon impeachment. But it would be implausible to make that claim once the Supreme Court has ruled that the President is legally entitled to resist those subpoenas.

If the Supreme Court rules in a timely manner on the side of the subpoenas, then Congress might have enough time to go forward with impeachment, with resistance to subpoenas as one possible charge, in addition to anything else they might find in the Mueller Report, or in the President’s financial records, or from other investigations.

In that case, President Trump has said that he will sue the House of Representatives in the Supreme Court for launching an impeachment campaign for no other reason than to remove him from office and to reverse the results of the 2016 election. Several legal experts, including Professor Lawrence Tribe of Harvard, have denounced this as an “idiotic” move that has no chance of success. The Supreme Court has ruled that the Constitution allocates the power of impeachment to the House and Senate alone, with no power of review given to the Court. In one relevant case decided in 1993 in the impeachment of a federal judge (Nixon v. United States), however, three justices (Justices Blackman, White, and Souter) issued an opinion stating that the Supreme Court should reserve the power to review impeachments should they be carried out arbitrarily, without cause, or without due process—which is what President Trump seems to be on the verge of arguing.

The Constitution lays out broad grounds for impeachment: “treason, bribery, or other high crimes and misdemeanors.” Because the Supreme Court has never intervened in an impeachment case, it has never ventured to provide a constitutional definition of these terms. But the Court might be tempted to do so if the House proceeds with impeachment charges that appear arbitrary, unreasonable, or excessively political in nature—especially if the House proceeds to impeach the President for resisting subpoenas that the Court has already ruled that he had a right to resist.

If we assume that the House of Representatives overcomes all of these roadblocks and votes out a bill of impeachment against the President, is the Senate then required to take it up and stage a trial? The Constitution gives to the Senate “the sole power” of trying impeachments. But does the Senate have an affirmative duty to take them up? These are open questions.

Senator McConnell has said that the Russia investigation is closed with the completion and publication of the Mueller Report, and that the Congress should move on to other business. Republicans, controlling a majority in the Senate, have said that the attacks on President Trump are hyper-partisan, driven by personal hatred, and motivated by a desire to reverse the results of the last election. In making such statements. Sen. McConnell and other Republicans in the Senate have sent clear signals to the House of Representatives that they may scuttle any trial on charges derived from the Mueller Report—particularly after Mr. Mueller wrote that his team could not identify any crimes committed by the President.

There are any number of steps the Senate could take to stonewall a partisan impeachment bill coming from the House. The Constitution does not specify the form that a trial should take. In the 1993 case cited above dealing with a federal judge, the Senate assigned the case to a committee that later reported its finding to the full body. Senator McConnell could do that again by burying the impeachment in a committee. He might refuse to schedule a trial, or delay it past the election or into a new Congress, or fill the calendar with other business (such as confirming federal judges), or adjourn without taking up the charges. In the trial of Andrew Johnson in 1868, the Senate voted on three charges but then adjourned without voting on several others.

In addition, any member of the Senate can request debate on the subject of whether or not to take up a bill of impeachment. Under Senate rules, sixty votes are required to end debate, so that forty-one members can prevent a trial from going forward by keeping the debate going. If forty-one members of the Senate decide the charges are flimsy and without merit, they would have little difficulty in scuttling the bill of impeachment. Speaker Pelosi has said that there is not much point in pushing for impeachment if conviction in the Senate is unlikely. That conclusion is doubly valid if the Senate is likely to embarrass the House by refusing even to take up the charges.

In such an unprecedented situation, the House of Representatives could go to the Supreme Court to request an order for the Senate to take up its bill of impeachment. Democrats in the House would find that a difficult case to make, however, especially if they have already argued against President Trump’s lawsuit that the federal courts have no power under the Constitution to intervene in impeachments. In that case, the Supreme Court would undoubtedly throw the question back to the House and Senate to fight it out.

It thus appears that there are many “roadblocks” in the way of removing President Trump through impeachment. He can delay the proceedings via lawsuits or deprive the House of information it requires to proceed with its investigations—and when all is said and done, he might persuade the Senate to bury without trial any bill of impeachment approved by the House, thereby bringing the whole enterprise to an embarrassing conclusion.

In the latter case, the President would be set up to go into the presidential campaign charging Democrats with mounting a four-year campaign to overturn the verdict of the voters, culminating with a bill of impeachment that was too flimsy and partisan even for the Senate to consider. This would provide the President with a strong case to make to the voters amid the institutional wreckage wrought by hyper-partisan Democrats. Those, like Professor Tribe and others, who are whining about “the rule of law” and a “constitutional crisis,” should think twice about where things are likely to stand on these fronts after this spectacle has run its course.