It took until the eve of the Iowa primary for the political commentariat to comfortably acknowledge something that’s been staring them in the face for months and months: Donald Trump is heavily favored to both pull off a victory in Iowa—the one early state where he’s tended to underperform in polls—and win the Republican Party’s presidential nomination.

How did we get here? How did the party that has recently been led by country-club candidates like Mitt Romney and Bob Dole come to be overtaken by a performance artist whom these former nominees detest? There are many answers to this question, some of which go back decades, but you don’t have to go back decades to see how the Trump phenomenon might’ve been avoided.

This year’s GOP primary has frequently been framed as a referendum on the party’s response to Romney’s defeat in 2012. After President Obama’s reelection, Republican Party leaders conducted an election postmortem and determined that the GOP’s fatal liability was its hostility to a variety of Democratic-leaning demographics, immigrant communities in particular. That report was the jumping-off point for a long and ultimately failed legislative effort to reform the country’s immigration system, provide a citizenship guarantee to America’s vast undocumented population—and allow the GOP to demonstrate a newfound respect for non-white voters.

In the Senate, where constituencies are diffused across states, a comprehensive bill passed handily. But it met fierce resistance from conservatives in the House, who forced votes on a variety of symbolic, immigrant-hostile legislation, while blocking comprehensive reform. When hostility to amnesty developed into the right’s signature obsession, the bill’s chief Republican pitchman, Senator Marco Rubio, turned his eyes to the presidency and abandoned his own undertaking.

Congress’s split verdict on immigration reform left the Republican Party’s post-2012 identity unresolved, and the ensuing presidential primary thus became a referendum on whether the GOP would hew to the RNC’s faltering recommendations, or fish instead in the deeper and unknown waters of disaffected white voters.