Mark Sanford, a former governor and former congressman from South Carolina known for his fiscally conservative views, will challenge President Donald Trump for the Republican presidential nomination.

Sanford announced his primary bid on Sunday morning during an appearance on "Fox News Sunday." He told host Chris Wallace that Republicans have "lost our way" during the Trump years, and said he hoped his entry into the race would help spark "a real conversation on debt and deficits and government spending." He joins former Massachusetts Gov. Bill Weld and former Illinois congressman Joe Walsh in trying to unseat Trump.

"I am compelled to enter the Presidential Primary as a Republican for several reasons—the most important of which is to further and foster a national debate on our nation's debt, deficits, and spending," Sanford wrote on Twitter shortly after his announcement. "We, as a country, are more financially vulnerable than we have ever been since our Nation's start and the Civil War. We are on a collision course with financial reality. We need to act now."

Though it seems unlikely that Sanford will prevail against Trump—more on that in a moment—the entry of a candidate who wants to discuss the growing national debt and annual budget deficits should be welcomed. The national debt has ballooned from $19 trillion to more than $22 trillion under Trump's watch, and the Congressional Budget Office says current policies have put the country on track for record-high levels of debt by the 2040s.

Sanford voted against the 2018 budget deal that passed a Republican-controlled Congress and was signed by Trump. He was no longer a member of Congress when another budget-busting spending plan was approved with bipartisan support and signed by Trump in July of this year.

In announcing his candidacy on Sunday, Sanford called Trump "king of debt"—repurposing a phrase Trump has used in the past to describe himself, positively, during his time as a real estate developer.

Politically, Sanford's effort—like Weld's and Walsh's—is almost certainly doomed to fail. Despite Trump's general unpopularity (just 39 percent approve of his handling of the job in the latest Gallup poll, while 57 percent disapprove), the current president is viewed favorably by more than 90 percent of self-identifying Republicans. In the few surveys that have included Trump's Republican primary opponents, Sanford has so far not polled above 4 percent and Weld has rarely broken into double-digits.

The GOP has become the party of Trump, and the sitting president seems to have little to fear from Sanford or other "Never Trump" Republicans. He seems to know it, too:

Can you believe it? I'm at 94% approval in the Republican Party, and have Three Stooges running against me. One is "Mr. Appalachian Trail" who was actually in Argentina for bad reasons…. — Donald J. Trump (@realDonaldTrump) August 27, 2019

Still, that only makes some recent decisions by Republican officials even more cowardly.

Republican parties in Arizona, Kansas, Nevada, and South Carolina are expected to cancel their 2020 primary elections, Politico reported earlier this week, in an attempt to limit the viability of the longshot anti-Trump efforts. Republican party officials and the Trump re-election campaign appear worried about an outcome along the lines of what happened in 1992, when upstart candidate Pat Buchanan scored 37 percent of the vote in the New Hampshire primary against incumbent President George H.W. Bush. Though Bush prevailed in the primary, the New Hampshire result changed the public perception of Bush and may have played a role in his eventual general election loss—the last time an incumbent president failed to win re-election.

The loss of the South Carolina primary—state party officials confirmed on Saturday that it would be scrapped—is a particular blow to Sanford, who may have been able to build some momentum against Trump with a good showing in his home state's election, which would have come early in the primary schedule.

But Sanford seems realistic about the limitations of his primary campaign. "I don't think anybody is going to beat Donald Trump," he told Fox News in July. When pressed by Wallace to assess his chances on Sunday, Sanford offered a slightly more optimistic view. "I'm saying you never know," he said.

Ironically, Trump's takeover of the GOP blunted what would have once been a disqualifying detail from Sanford's bio. He infamously disappeared for six days in July 2009—supposedly to hike a portion of the Appalachian Trail. In fact, he was having an extramarital affair with an Argentine woman, María Belén Chapur. Though he finished his term as governor, the incident changed the course of his political career.

Prior to La Affaire Argentine, Sanford was regarded as a possible White House contender. Following Ron Paul's 2008 dark horse presidential run, he and then-governor of New Mexico Gary Johnson (along with, of course, Rand Paul) were often identified as the heirs apparent to the libertarian wing of the GOP.

"I wear it as a badge of honor, because I do love, believe in, and want to support liberty," Sanford said in 2009 when he was labeled a "libertarian" by Sen. Lindsey Graham (R–S.C.).

In the age of Trump, adultery is hardly political suicide anymore. But is there room in the Republican party for a fiscal conservative who opposes bailouts, loves Atlas Shrugged, and disdains political tribalism?

Probably not. When Sanford was defeated by a Trump-backed primary challenger in June 2018, the president openly celebrated the then-congressman's second political demise with a tweet suggesting Sanford "would be better off in Argentina."

That the thrice-married Trump, who has had at least one extra-marital affair with a porn star, has shown no reservations about attacking Sanford for his own infidelities provides a pretty good illustration of the current state of the GOP's collective moral compass.

That Sanford is likely heading for an electoral pasting—one that he will receive while trying to talk substantively about the importance of the debt crisis facing America, while the current figurehead of the Republican Party retweets memes—provides an equally useful illustration about the health of his party.