The Republican presidential primary is all but over. Even if Nikki Haley stays in the race, it’s hard to see her winning a single primary, including the one in her home state of South Carolina next month. Even though Haley received an impressive 43 percent of the New Hampshire vote, her electoral reality is grim. According to the most recent FiveThirtyEight polling averages, she trails Donald Trump by more than 56 points nationally and by 37 points in South Carolina.

It’s déjà vu all over again. Since the moment Trump took the G.O.P. primary lead in 2015, he’s never relinquished his hold on the party. And since Trump’s hostile takeover and unexpected 2016 victory, the G.O.P. has also experienced consistent losses. Democrats seized the House from Republicans in 2018. They took the presidency and the Senate in 2020. In those two elections, the Democrats accomplished a political feat not seen since the Herbert Hoover era: winning the House, Senate and White House in a single four-year span.

And the Democrats’ success didn’t stop there. In 2022, despite political conditions that should have been overwhelmingly favorable to Republicans, Democrats made a modest gain in the Senate and barely lost the closely divided House. Election-denying MAGA candidates were routed in multiple swing-state elections. Yet none of those setbacks broke Trump’s grip on the G.O.P.

This is in part because while Democrats have been able to mobilize an effective anti-Trump opposition, conservative Never Trumpers — Republicans and former Republicans like me who have desperately tried to break Trump’s grip on the party — mostly failed. It’s now clear to me that we never had a chance. And the reason is equally clear: We did not truly understand our own party.