Presidential impeachment looms, and perhaps even removal, because Donald Trump may have colluded after all.

Or, to use the correct legal terminology, maybe the president tried to engage in a “conspiracy” with a foreign government, to wit, an effort to use American assets in a quid pro quo arrangement to directly affect a national election and both nations’ systems of criminal justice.

This is what House Intelligence Committee Chairman Adam Schiff of California and other Democrats suspect with regard to a whistleblower’s complaint that reportedly was “prompted by President Trump’s interactions with a foreign leader.”

The evidence already indicates a significant likelihood that the suspicions are correct. If — repeat, only if — the reports do prove true, then Trump is in massive trouble.

Granted, Schiff himself is hardly a reliable interpreter of events. He’s a far-left ideological enemy of Trump’s, a publicity hound prone to grandstanding, gullibility, and prevarication. Still, even political hacks sometimes stumble upon important information.

What’s known is this: First, former Vice President Joe Biden is suspected by many in Trumpworld of having used undue influence to kill a Ukrainian investigation into potential illegalities by his son, Hunter. If Biden did so, that would almost surely be illegal and would by all reasonable standards make him unfit for the presidency.

It is not, however, obvious that Biden did what is suspected. Trump and his attorney Rudy Giuliani, though, obviously want Ukraine to r-open the investigation into Biden. It long has been evident that Trumpworld believes that among the current Democratic presidential candidates, Biden would be his most serious challenger. If Ukraine finds Biden actually did something wrong, or even if they publicly are investigating him, Trump’s reelection prospects surely would improve.

Hence, Giuliani’s now-admitted efforts to ask Ukraine’s current regime to ensnare Biden in a major investigation. If Giuliani did so at Trump’s request, which is certainly not far-fetched, that alone would be dicey behavior. As the United States is a key ally for Ukraine’s very survival, any implied pressure on it from someone acting for the president, on behalf of the president’s political interests, would be ethically questionable.

Yet Trump is now suspected of doing even worse, than that. A whistleblower filed a report to the inspector general for the U.S. intelligence community — a complaint the White House is withholding from Congress, but whose existence if not exact details are known — alleging an “urgent” matter arose from a “promise” Trump made in a phone call with a foreign leader. Available evidence makes it almost certain that the complaint involved July 25 call to Ukrainian President Volodymyr Zelenskiy, at a time when Trump was delaying a $250 million military assistance package for Ukraine already approved by U.S. law.

Trump subsequently allowed the aid to go forward.

In sum, Democrats suspect Trump conditioned the aid delivery on Ukraine’s willingness to investigate Biden.

Every bit of circumstantial evidence so far, including Giuliani’s similar mission and including a Ukrainian official summary of that July 25 phone call, makes that suspicion entirely plausible. If so, it would be a serious conspiracy indeed.

Substitute “Ukraine” for “Russia,” in this sentence from special counsel Robert Mueller’s explanation (p. 66) as to what potential crime he was investigating: “coordination or conspiracy … with respect to Russia providing assistance to the campaign in exchange for any sort of favorable treatment in the future.” In the new Ukraine case, the suspected quid pro quo is obvious and far worse than what Mueller investigated. If the president uses U.S. taxpayer-financed military supplies as, in effect, a bribe to induce a foreign government to harass the president’s domestic opponent, it’s a horrible crime.

If it is true, this is a scandal much worse than Watergate. If it’s true, Trump must be removed from office.