When Rubio launched his campaign 11 months ago in Miami, he was the favorite of many Republicans, but not the frontrunner. Fans and critics alike had been labeling him the GOP’s version of Barack Obama since well before Time Magazine plastered him on its cover in early 2013 under the headline, “The Republican Savior.”

It was easy to see why.

A first-term senator in his 40s, Rubio was, like Obama, a gifted orator with a biography that embodied the American dream. He wowed Republicans with his speech at the party’s convention in 2012, and his supporters saw a strong general-election candidate who could easily loosen the Democrats’ tight grip on the Hispanic vote. Rubio frequently invoked his working-class, immigrant parents, who came to the United States a few years before Fidel Castro took power in Cuba. “My father stood behind a small portable bar in the back of a room for all those years, so that tonight I could stand behind this podium in the front of this room,” Rubio said in a signature line from his announcement speech last April.

Like Obama in 2008, he sought to head off questions about his youth by calling for a generational turnover, a changing of the political guard. “Now, the time has come for our generation to lead the way toward a new American century,” Rubio said in a line that he hoped would work both against Jeb Bush in the primary and Hillary Clinton in the fall.

Yet for all of the hype, Rubio faced two major hurdles even before Trump got into the race. The first was the history of the GOP: Much more so than Democrats, Republicans have tended to nominate next-in-line candidates—those with deep governing experience or long tenures on the national stage. In the last 50 years, the only non-incumbent to win the Republican nomination who had not previously run for president was George W. Bush in 2000, and he was the son of a president and a two-term governor of Texas. For many Republicans, that candidate in 2016 was Jeb Bush, who moved quickly to sign up donors and staff who might otherwise have gone to Rubio.

In that sense, the comparisons to Obama hurt Rubio as well. For six years, Republicans had been telling voters it was a mistake to elect a president who hadn’t even completed a single term in the Senate. Furthermore, the conventional wisdom heading into the 2016 race was that voters disgusted with Washington politics would gravitate toward a governor, a dynamic from which Bush, Scott Walker, Chris Christie, Rick Perry, John Kasich, or Bobby Jindal stood to benefit.

The other big problem for Rubio was immigration. At a time when the Republican National Committee was formally calling for the party to embrace comprehensive reform, Rubio joined the Senate’s Gang of Eight in 2013 and tried to sell conservatives on legislation that offered an eventual path to citizenship to undocumented immigrants. The bill passed the Senate but never came up in the more conservative House, where hardliners denounced it as a form of amnesty. Rubio quickly renounced the legislation, but as the 2016 campaign began, he had lost support among conservatives who criticizing his original support for the proposal as well as from Democrats and reform-minded Republicans who said he had cut and run on a critical issue.