It ain't over till the fat lady sings

Not sure whether that makes Republican Senators more or less likely to vote for impeachment this time around, but it's good to know.

And here's another thing you might not realize (I didn't anyway): If  After Trump is impeached, he can't be pardoned. He WILL be impeached. This may be why Richard Nixon resigned before being impeached - in order to get Ford's pardon.

So if there's no chance of getting the 20 Republican votes needed to convict Trump and send him packing, is there any reason for the House to impeach him?

Yes. There are three reasons.

The first is the Constitution itself. Donald Trump has openly and brazenly abused his power—not only seeking electoral help from foreign nations but making money off his presidency in violation of the emoluments clause, spending funds never appropriated by Congress in violation of the separation of powers, obstructing justice, and violating his oath to faithfully execute the law.

[...]

The second reason is political. While the impeachment hearings don't appear to have moved Republican voters, only 29 percent of Americans still identify as Republican.

  Newsweek

Whaaaaaat???

The hearings do seem to have affected Democrats and independents, as well as many people who sat out the 2016 election. National polls by Morning Consult/Politico and SSRS/CNN show that 50 percent of respondents now support both impeaching Trump and removing him from office, an increase from Morning Consult/Politico's mid-November poll.

Presumably anyone who now favors removing Trump from office will be inclined to vote against him next November. The House's impeachment could therefore help swing the 2020 election against him.

The third reason for the House to impeach Trump even if the Senate won't convict him concerns the pardoning power of the president.

Assume that Trump is impeached on grounds that include a raft of federal crimes – bribery, treason, obstruction of justice, election fraud, money laundering, conspiracy to defraud the United States, making false statements to the federal government, serving as an agent of a foreign government without registering with the justice department, donating funds from foreign nationals, and so on.

Regardless of whether a sitting president can be indicted and convicted on such criminal charges, Trump will become liable to them at some point.

[...]

Article II, section 2 of the Constitution gives a president the power to pardon anyone who has been convicted of offenses against the United States, with one exception: "In Cases of Impeachment."

If Trump is impeached by the House, he can never be pardoned for these crimes. He cannot pardon himself (it's dubious that a president has this self-pardoning power in any event), and he cannot be pardoned by a future president.

Even if a subsequent president wanted to pardon Trump in the interest of, say, domestic tranquility, she could not.

[...]

The House will probably impeach him before Christmas.

After that, he will be quite literally unpardonable.

He may yet make a Spiro Agnew-type deal before it's all over.