House Speaker Nancy Pelosi is gloating because President Trump is “impeached for life,” and “there’s nothing the Senate can do that can ever erase that.” Like a prosecutor telling a defendant, “Even if acquitted, you’re indicted for life, and you’ll never shake the disgrace.” So much for the noble principle of innocent until proved guilty.

Could this be the same never-hate Pelosi who wore black on ­Dec. 18 as she “solemnly and sadly” called for a vote to impeach the president? What a charade. The Democrats’ goal all along has been to impeach the president and damage his re-election in 2020.

The House will soon transmit the ­articles of impeachment to the Senate, where a trial will commence next week. Already Pelosi and Senate Minority Leader Chuck Schumer are conspiring to smear Trump’s likely acquittal as a cover-up. To make the disgrace stick.

Pelosi and Schumer have been demanding an upfront guarantee that the Senate will call White House staff as witnesses, knowing that’s a nonstarter with Mitch McConnell. The majority leader prefers the trial format used for Bill Clinton’s 1998 impeachment: First, the House presents its charges, then Trump’s lawyers rebut. If the senators need to know more, they can call witnesses. Delaying that decision doesn’t mean the trial is rigged.

Some Trump supporters are urging the Supreme Court to step in to halt the Senate trial before it ­begins. That will go nowhere, ­because the court ruled unequivocally and unanimously in 1993 that it wouldn’t interfere in impeachments. It’s up to the Senate to question the wisdom of degrading impeachment into a mere partisan tool. Allow it now, and any future House majority can impeach a president it doesn’t like.

After all, House Democrats argued that Trump can be impeached even if he hasn’t broken any law. Their first article of impeachment accuses him of putting “personal political benefit” ahead of “the interests of the nation.” That’s such a vague and subjective standard, it could ensnare any president. Senators should reject it.

Democrats charge Trump with a second offense, “obstruction of Congress,” for claiming executive privilege and refusing to allow White House staff to testify. But executive privilege isn’t something Trump invented. Previous presidents, from George Washington to Barack Obama, have said “no” to congressional requests, relying on the courts to referee disputes.

This time, House Democrats were in a rush to impeach and ­unwilling to battle Trump in court. They took a shortcut around our constitutional system of checks and balances. Senators shouldn’t go along with it.

The Senate could vote to dismiss the articles, on the basis that these charges aren’t impeachable ­offenses. Trump called for that on Sunday, but there is no political will among Senate Republicans to take the heat for that. And truth is, acquittal is better than dismissal.

So, after opening arguments, senators will decide whether to reach a verdict or call witnesses. Democrats are running ads against vulnerable Republicans like Maine’s Susan Collins accusing them of unfairness for not guaranteeing witnesses, and it’s having an impact. Collins indicated Friday that she will try to get witnesses called. Rand Paul is rightly insisting that include witnesses Dems might not like, such as Hunter Biden.

But calling witnesses isn’t the same as getting them. Even if the Senate votes to subpoena White House staff, not least former ­National Security Adviser John Bolton, don’t count on hearing from them. Trump intends to limit or block testimony, including Bolton’s, citing executive privilege. Bolton may defy Trump, but Trump’s current top advisers probably won’t.

Ordinarily, Trump’s stance would ignite a court battle. Dems lost their chance for that once they voted to impeach. The 1993 ruling suggests the Supreme Court will no longer intervene. That means there is no practical way to force the president to produce witnesses.

Expect a short trial, an acquittal and no relief from the venomous anti-Trump rancor driving the Democratic Party. House Democrats are looking for new grounds to impeach. As if Congress had nothing better to do.

Betsy McCaughey is a former lieutenant governor of New York.