There are only two arguments against the impeachment of Internal Revenue Service (IRS) Commissioner John Koskinen, as it comes up for a vote in the House of Representatives on Thursday.

The first is that the Senate is unlikely to convict Koskinen, since conviction requires a two-thirds majority. The second argument is that Koskinen’s sin — allowing key evidence in the IRS scandal to be destroyed and misleading Congress about it — does not rise to the level of “high crimes and misdemeanors.”

The fact that Democrats will not convict Koskinen is not a reason to deny them the opportunity. In fact, that is all the more reason to impeach him.

Let them hear the evidence — how Congress re-issued a subpoena for the emails of former Exempt Organizations head Lois Lerner; how backup tapes of Lerner’s emails — mysteriously destroyed on her hard drive — were erased by IRS employees; and how Koskinen did not inform Congress, instead claiming Lerner’s emails were unrecoverable.

Let Democrats then vote to protect a senior public official who enables that kind of cover-up — and the head of the IRS, no less, who would pursue ordinary Americans with audits, fines and possible criminal referrals if they tried to do the same.

The Democrats demanded that the IRS target conservative groups, and benefited politically in 2012 when hundreds of Tea Party groups were immobilized by the agency. Let them now suffer the political consequences in 2016. That is a form of justice.

Some Republicans fear a public backlash against impeachment, remembering that the impeachment of President Bill Clinton hurt their party’s political fortunes. But there is a huge difference between the two: Clinton was elected by the people, while Koskinen is just a political appointee with no constituency or public sympathy. When his mismanagement and contempt for Congress and the public are held up to the light of public scrutiny, Senate Democrats may well decide to change their minds.

As for the second argument, Koskinen’s conduct is certainly impeachable. The Constitution provides (Art. II Sec. 4): “The President, Vice President and all civil Officers of the United States, shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other high Crimes and Misdemeanors.” Destroying evidence under subpoena is a crime, as is lying to Congress.

The Justice Department — which is implicated in the IRS scandal, and let Lerner off the hook — will never prosecute Koskinen. Impeachment is therefore not only an appropriate remedy, but the only one that is available.

Imagine what happens if Koskinen is not impeached. A Republican Congress will have failed to punish anyone for the IRS scandal, one of the most egregious abuses of power in recent American history. A dangerous new precedent will have been set for trampling constitutional rights, for cover-ups and for deceit.

The media are casting Thursday’s vote as a test of Speaker Paul Ryan’s leadership — i.e. whether he can stand up to the conservative Freedom Caucus. On the contrary, the impeachment of the IRS commissioner ought to unify the Republican Party. In a less partisan political environment, it might also unify the country.

No American should be subject to the abuse and invasions of privacy that the IRS perpetrated. Koskinen was brought in to restore public trust. Instead, he made the scandal worse. He has to go — and impeachment is the only way to do it.