One thing is clear: Congressman Ken Buck will depart office next January with a far different fan club, and for that matter a different set of naysayers, than when he showed up in Washington 10 years prior.

Buck’s newfound critics of late, not a small number or a quiet bunch within activist Republican ranks, have all manner of theories. He went soft. He lost the will to fight. He’s trying to land a CNN gig. Some even suggest a love interest has pulled him away from his longstanding partisan axis.

I have not yet heard of a secret-agent theory or one that involves compromising photos. Though, no doubt, those and other stretches are floating out there as well.

To attend the we-don’t-have-a-stage-big-enough forum of GOP candidates hoping to take Buck’s place, a group now numbering 11, is to hear Buck’s name seldom mentioned, and on those few occasions in disparaging terms.

This crew of candidates – which until proven otherwise I regard as Jerry Sonnenberg, Deborah Flora, some interloper from western Colorado and the amorphous rest – are far more focused on the roaring approval of the Trump base than on any nod from a departing congressman who decided that base was something short of all-knowing.

That Trumpian crowd sees Buck as a changed figure with that change not to their liking. Buck presents himself as a model of consistency in a party that has changed around him and lost its adherence to Constitutional principle.

Buck has never come across as the waffling or weak-kneed type. Fresh out of law school, he was hired by Wyoming Congressman Dick Cheney in 1986 to work on the Iran-Contra investigation. Four years later, he moved to Colorado and became head of the criminal division in the U.S. Attorney’s office.

Having worked with successful Colorado Republicans of that era, including Bill Owens and Wayne Allard, Buck got himself elected Weld County District Attorney in 2004.

In 2010, he became a statewide figure in seeking the U.S. Senate seat then held by an appointed Michael Bennet. Many thought him poised to win this election in a red year in what was then still a very purple state.

But a couple of gaffes cost him dearly. A needless jab at his primary election opponent for her “high heels” did not go over well with women voters. In an October debate on NBC’s “Meet the Press,” Buck wandered off-script in response to a question about gay rights, describing homosexuality as a “choice” and comparing it to alcoholism in that regard.

It all was enough to allow Bennet to overcome the national tide and secure a narrow victory.

Buck campaigned in 2010 as the Tea Party candidate just as that affiliation became a major part of the political landscape. Come 2014, when then-Rep. Cory Gardner sought and won a Senate seat, Buck put on his Tea Party hat and easily maneuvered his way to the Republican nomination. That is tantamount to election in this solidly Republican district. His reelection races have been perfunctory affairs.

At some point between 2014 and 2016, the Tea Party morphed into MAGA, the Trump-led Make America Great Again movement. To many observers, these were one and the same crusade. However, that was not Buck’s take, certainly not as time went on.

In Buck’s telling, the Tea Party was rooted in reverence for the Constitution and an uncompromising dedication to fiscal restraint and budgetary reform.

MAGA has become something quite different in Buck’s view. He described MAGA as too often “cavalier about the Constititon” and their champion, the former president, “not rooted in traditional conservative values.”

That is as true as it is damning. He went on to note that Republicans in MAGA’s grip have sacrificed any claim to fiscal responsibility and putting the country’s financial books in order.

I would add – though, to be clear, this piece is my perspective, not anything Buck stated – that MAGA has evolved into a charismatic enterprise, with cult-like loyalty, far too centered on the whims and grievances of one, singularly unworthy person, with a disregard displayed too often for basic facts and an overdose of ends-justify-the-means thinking.

In MAGA-land, otherwise known as today’s Republican Party, Buck’s heresies have been multiple. A few hours after the disgrace of Jan. 6, he voted to certify Joe Biden’s election as president. That alone put him at odds with two-thirds of his caucus and both of Colorado’s other GOP representatives.

He criticized the fixation of some Republicans with impeaching Biden. He defended Liz Cheney as the House GOP caucus threw her overboard for the crime of telling the truth. He issued a four-page, point by point, footnoted rebuttal to some Jan. 6 myths peddled by El Paso County Republican officials.

Most recently, Buck was one of three lonely Republicans to vote against impeaching Homeland Security Secretary Alejandro Mayorkas. This dissenting vote was not borne of Buck’s approval of Mayorkas’s performance. Anything but. Instead, it resulted from Buck’s conviction that the charges did not rise to the level of high crimes and misdemeanors, the Constitutional standard.

Buck has always struck me as a complicated sort. In my book, that is a compliment. His motives are not typically easy to decipher.

To add to the insults his Republican critics now lob at him, they suggest that the author of “Drain the Swamp,” Buck’s 2017 book that led to an HBO documentary, has become an inhabitant of that swamp.

Hardly so from where I sit. Swamp creatures seek to overstay their time in the office. Such types rarely stand on principle. In today’s GOP, the swamp hustlers contort themselves to stay in Trump’s good graces at the expense of their own spine and self-respect. Examples abound.

Buck contends that he will leave Congress as he arrived, as “a Constitutional conservative.” By his account, he has been true to form while his party backed away from principle time and again.

A recap of Buck’s tenure is not complete without mention of two formidable health crises he survived. He has come back from both Stage 4 lymphoma and a major heart attack.

Now 65, Buck attests that those experiences further molded him. “They reinforced my mortality and the knowledge that my time is limited.” He went on, “I am a person of faith and believe God put me here. I intend to leave Congress with the same consistent worldview with which I arrived.”

Whether in the person of Bob Corker or Jeff Flake, Liz Cheney, or Peter Meijer, along with too few others, it is a sad commentary and also a telling one that Republicans of this period are able to speak hard truths only when hitting the exits or accepting political defeat.

Add Colorado’s Ken Buck to that list. Trump and his worshipping acolytes can preen and flex their muscle. While the nation suffers in retreat.

Eric Sondermann is a Colorado-based independent political commentator. He writes regularly for ColoradoPolitics and the Gazette newspapers. Reach him at EWS@EricSondermann.com; follow him at @EricSondermann