President Trump Bet Big This Election Year. Here’s Why He Lost.

Some of the president’s advisers were mystified, therefore, that the White House would repeatedly send him to a state irrelevant to his re-election for a candidate he scarcely knows, Eddie Rispone, after they had just been scalded in their attempt to rescue Mr. Bevin in another safely red state.

In Congress, Louisiana lawmakers and their aides grumbled that Mr. Trump was not being shown quality polling indicating how formidable Mr. Edwards was with Republican-leaning voters. And some in the delegation pointed a finger at Louisiana’s voluble junior senator, John Kennedy, who has become a close White House ally, for pushing the president to campaign in the state.

But the president was receptive to Republicans who told him he could be the difference-maker in these elections, according to G.O.P. officials briefed on the discussions.

One of those people said that Ronna McDaniel, the Republican National Committee chairwoman, had been preparing the president for the past two weeks for the possibility of a Louisiana loss. That’s because early voting patterns showed Democrats mobilizing their core voters, especially African-Americans.

Mr. Trump’s supporters defended him, noting that Republicans won down-ballot in Kentucky and captured the Mississippi governor’s race, while arguing that he would benefit from a polarizing opponent next year.

“The gubernatorial results in 2019 in Kentucky and Louisiana are in no way a referendum on President Trump or a foreshadowing of the 2020 presidential election,” said the R.N.C. spokesman Mike Reed. “The Democrats who ran for governor in those red states aren’t anything like the far-left candidates running against President Trump.’’

Still, the main instigator for the president’s involvement in the races, many Republicans said, was Mr. Trump himself, who simply craves the adulation of his supporters and is singularly focused on notching victories, no matter the details. He is even more eager to flex his political muscle in the face of impeachment, and has surrounded himself with several aides who either defer to his whims regardless of the neon-flashing signs of risk before them, or know little about politics.

People close to Mr. Trump — who spoke anonymously to discuss sensitive matters — said he viewed the campaigns he had weighed in on mostly as opportunities for gratification. And with few seasoned political advisers in his inner circle — his son-in-law, Jared Kushner, who has control over the president’s campaign, has never worked on another race — there was nobody to tell him that attacking an anti-abortion rights, pro-gun Democrat like Mr. Edwards as a radical would be folly.

“There were people who are normally part of the Republican base who voted for the governor,” said Senator Bill Cassidy of Louisiana, noting that the portrayal of Mr. Edwards as a liberal extremist was ineffective given his views on cultural issues and credentials as a West Pointer turned Army Ranger. “He’s a very likable man and a man of character.”

Of course, plenty of well-credentialed and well-liked candidates have fallen prey to the forbidding political demographics of their states or districts.