The worm has turned.

For months, Democrats agonized over whether to impeach President Trump. Would it cause them to lose House seats? Would it hurt their chances of winning the Senate? Wasn’t it pointless because of the near certainty the Republican Senate wouldn’t convict him?

But Trump just made the Democrats’ choice for them. He left them no alternative but to proceed with impeachment – and they will.

The president admitted Tuesday that he withheld congressionally approved military aid to Ukraine just days before a phone call with the Ukrainian president in which he demanded Ukraine produce dirt on Trump’s likeliest Democratic opponent. That, on its face, is a flagrant abuse of power and nearly identical to the behavior, denied by Trump, at the core of the Russia investigation: seeking a foreign government’s help in a U.S. election.

It is the latest instance of him using the levers of government for his own political ends, to enrich himself, to reward friends and to punish opponents. This is the stuff of tin-pot dictatorships, not the United States. If the Constitution means anything at all, Congress must seek his removal.

Now that Democrats are pursuing an impeachment inquiry, the pressure – and the quandary – shifts. The question now is whether Republicans, who have tacitly endorsed Trump’s behavior so far, will go on record to uphold the propriety of this conduct and in doing so, affirm the constitutionality of such behavior not just for him but for presidents to come.

Republicans (who decided that perjury about sex was impeachment-worthy, and who thought it an abuse of power to defer deportations of certain illegal immigrants) must now decide whether to accept Trump’s standard as proper for future presidents. Would Republicans, with their votes on Trump’s impeachment, condone the actions of, say, future President Elizabeth Warren when she:

• Defies congressional power of the purse by unilaterally raiding the Pentagon budget to finance her pet projects?

• Rejects the authority of congressional oversight, disregards subpoenas and refuses to furnish documents, including a whistleblower complaint about the president deemed “urgent” by the intelligence community?

• Is found by an independent prosecutor appointed by her own administration to have engaged in 10 possible instances of obstruction of justice but is not charged because regulations prohibit such a move against a sitting president?

• Approves and reimburses secret payments, in violation of campaign finance law, to a person threatening to put out damaging information about her?

• Fires an FBI director who refuses to call off a probe of one of her close associates?

• Rescinds the security clearance of a former CIA director critical of her, as well as the press credentials of journalists who criticize her administration?

• Persuades a foreign leader not to admit Republican members of Congress into his country?

• Repeatedly releases highly classified intelligence, some to a foreign enemy and some only to Democrats?

• Threatens to cut off highway funds and disaster aid to states and territories controlled by Republicans, and declares she has the “absolute” right to move criminals to jurisdictions governed by Republicans?

• Funnels millions of taxpayer dollars to her own businesses, pressures federal agencies and international organizations to do business with her personal enterprises, invites foreign governments to pay millions of dollars to her businesses, and rejects a law requiring her to provide Congress with her tax returns?

• Calls for a boycott of the parent company of a media outlet critical of her, threatens an antitrust action against the owner of another media outlet critical of her, says she can unilaterally order businesses to disinvest from a country and calls for federal punishment of individual businesses she doesn’t like?

• Offers to pardon those who commit crimes enforcing her policies and pardons a political ally who ignored court orders?

• Without congressional approval, establishes a de facto network of internment camps, run under inhumane conditions, for a class of people she disdains?

• And, finally, asks and coerces foreign governments to sabotage her Republican opponents’ campaigns?

Republicans have blessed all of this and more with their silence. They must now state their positions explicitly. If they vote to accept such conduct by this and, therefore, future presidents, the American experiment will be badly damaged. But if they aren’t at least forced to answer the question, it has already failed.