It is difficult to overstate the political currency of being labeled a “fighter.” As Liam Donovan, a Republican strategist, put it, the only thing more universal than a party’s desire for fighters is the belief that only the other side has them. This was particularly true for Republicans in President Barack Obama’s first term, even after they installed John Boehner as speaker.

“At that time, you started to hear grousing about how weak Republicans were, particularly Boehner,” Mr. Donovan said. The prevailing line of thinking, he explained, was that “G.O.P. leadership is always weak, and we need someone like Harry Reid who’s willing to be strong.”

Perhaps no leader in recent memory has haunted the Republican Party quite like Mr. Reid, the Senate majority leader from 2007 to 2015. Here was a man who appeared to heed Mr. Obama’s call during the 2008 election, when he reminded supporters of “the Chicago way,” as immortalized by Jimmy Malone in “The Untouchables”: “If they bring a knife to the fight, we bring a gun.”

For Republicans, the assumption of a knife may have seemed generous. Lawmakers like Mr. Boehner rose on the promise of legislative victories, only to have Mr. Reid ensure that most House spending bills never saw the Senate floor. While Republicans did manage to secure the occasional half-loaf, be it an extension of Bush-era tax cuts or the imposition of automatic budget cuts, it was never enough to dispel an underlying sense of futility. As conservatives saw it, government-funding negotiations inevitability ended in spending packages that largely took care of Democratic priorities, coupled with the image of a Republican Party that had yet again capitulated.

All of which may have fueled the party’s deep “resentment” for Mr. Reid and the left writ large, Mr. Donovan has written. But those feelings, he noted, were “often tinged with envy, if not begrudging admiration.”

Indeed, Mr. Reid helped entrench the perception that Democrats were willing to play hardball — and, more important, that they were all willing to play hardball. There were no stragglers, it seemed, in Mr. Reid’s party, no Susan Collinses or Lisa Murkowskis to fret over.