How long does it take for a good man — a farmer from Big Sandy, Montana — to become thoroughly corrupted by the lies and evil ways of Washington? Less than two terms in the U.S. Senate, it turns out.

Since the start of the republic, Americans have always tinkered with the idea of term limits for politicians in Washington. The Founders, of course, envisioned a citizen-legislature gathering in The Swamp along the Potomac for limited periods of time to take care of the nation’s business before returning to their real lives back home.

But, because of the unimaginable success of The Swamp, being in the legislature has become a full-time job. These days, many people come to Washington — and never leave.

So much power is an inebriating elixir. And there is so much money it would make King Midas blush.

The latest proposal for term limits comes through legislation offered by Rep. Francis Rooney, Florida Republican, who would like to slash the pay of all congressmen in the House or Senate after they have “served” in Washington for 12 years.

Under Mr. Rooney’s proposal, annual pay would drop from roughly $174,000 to just $1 after a member had been in Washington a dozen years.

There are all kinds of problems with this idea. But what is striking about it is how much this and other term-limit proposals reveal about how much people hate Washington.

Some people do not like Democrats. Some do not like Republicans. Some do not like Big Government politicians. Some people do not like politicians who pretend to be big global diplomats.

The one thing that unites just about everybody in America is their hatred for any politician currently in office. Thus, the allure of term limits.

Throw all the bums out!

My problem with this term-limit proposal — as with just about every term-limit proposal — is that it takes the vote out of the hands of voters. Every election we have should be a term limit in itself.

This particular term-limit proposal has another problem in that the term limits would effectively apply only to people who are not independently wealthy. If we learned nothing else from John Kerry and Mitt Romney, we learned that rich people with nothing to do do not make good political leaders.

My last concern is that — as with most term-limit proposals — this one would take power away from certain less-wealthy longtime politicians (a good thing) and basically hand that power over to lifelong staffers who have learned all the ins and outs and back channels of power in The Swamp (a terrible thing).

If there is anyone more dangerous than a lifelong elected Washington politician, it is a lifelong unelected Swamp staffer.

All of which brings us to Sen. Jon Tester, the Montana farmer turned hack Democrat.

He went to Washington as an affable guy who seemed to only want to serve his constituents back home. Twelve years in, Mr. Tester has turned into a swamp creature who finds sport in sliming the name of a Navy rear admiral who had a sterling reputation.

Before getting mashed into Mr. Tester’s insidious meat grinder, Adm. Ronny Jackson enjoyed universal, bipartisan praise for his service as the president’s doctor.

Upon being nominated to take over the disastrous Department of Veterans Affairs, the doctor became a political target.

Mr. Tester supposedly heard completely unsubstantiated accusations that the doctor was a drunken partyer who once wrecked a Secret Service vehicle after a party. (Funny, I don’t remember the Montana farmer sliming his former colleague, Sen. Ted Kennedy.)

Before confirming one word of the crazy allegations, Mr. Tester went directly to the media and aired it all. “Candy Man,” he called the rear admiral.

And, in a flash, another political opponent annihilated.

Now, Mr. Tester is the giant, pasty face of term limits. He is the embodiment of why people hate Washington politicians.

Luckily for the republic, the swamp creature this fall faces the ultimate term limit: an election. In Montana.

Where President Trump won by 20 points. And Mr. Tester has never broken 50 percent of the vote.