Update: Coverage of the second Republican debate.

One argument for dismissing Donald Trump's rise is that we've seen this movie — or at least this trashy reality show — before. The GOP base had a series of embarrassing flings in the 2008 primary, falling in and out of love with a list of unlikely candidates. There's no real reason to believe the flirtation with Trump will be any more lasting. As evidence, the Washington Post's Philip Bump tweeted this chart, which places Trump's rise in context of the temporary leads Newt Gingrich and Rick Perry secured in 2012:

There are two things to say about that. The first is that it's actually pretty impressive that Trump is matching Newt Gingrich and Rick Perry. Gingrich is the former Republican speaker of the House. Perry was the longest-serving Republican governor when he ran for president in 2012, and he was rightly considered a serious candidate before his collapse in the debates. Trump is an ideologically heterodox rich guy who fires people on a reality television show and who is disliked by practically everyone in the Republican establishment.

But the bigger point is that this time was supposed to be different. The 2012 GOP nomination was supposed to be an aberration. It was a mess. The base seemed desperate to nominate anyone who wasn't Mitt Romney. At different times, Michele Bachmann, Herman Cain, Rick Perry, Newt Gingrich, Rick Santorum, and, yes, Donald Trump, all led the polls.

The common explanation for the crazy, carousel-like nature of the campaign was that the Republican field was weak. The young Republican stars who thrilled Republicans in 2010 and 2012 — Marco Rubio, Chris Christie, Paul Ryan, Ted Cruz, Rand Paul, Scott Walker, and so on — weren't running. The 2012 GOP field was a throwback to the pre–Tea Party GOP. It represented a party that conservatives had already begun to replace. The new leaders — the leaders who felt current to the moment — weren't yet ready to run. But they would be soon.

"The past few election cycles have been grim," wrote Joseph Curl at the Washington Times. "The Republican Party went with Sen. John McCain because, well, it was his turn (just like in 1996 with Sen. Bob Dole). Pretty much the same thing in 2012 with Mitt Romney." But the future, he said, was bright. "Republicans are sitting on the deepest bench they've had in decades."

The future is now. The GOP's 2016 field has successful governors from purple states like Ohio's John Kasich, Florida's Jeb Bush, and Wisconsin's Scott Walker. It has, in Chris Christie and George Pataki, popular (or at least once-popular) governors from blue states. It has three of the Tea Party's leading voices in the Senate: Marco Rubio, who seems able to appeal to moderates and Latinos; Rand Paul, who is trying to build a libertarian-inflected version of the Republican Party that might better appeal to young people; and Ted Cruz, who is so uncompromising he shut down the government rather than let Obamacare advance, at least at one point. For the 2012 nostalgics, Rick Perry and Rick Santorum decided to run. For anyone who thought the government should be run more like a business, Carly Fiorina jumped in the race. Even Mike Huckabee decided to give it another shot.

2016 was supposed to be a year when Republicans were spoiled for choice. 2016 was supposed to be a year when Republicans couldn't decide which uber-qualified, intensely charismatic, deeply conservative candidate to choose from.

Instead, a growing plurality of the base has fallen in love with Donald Trump. Imagine how frustrating that is for this field of candidates, most of whom have spent the last few years proving and re-proving their conservative credentials. As Jonathan Chait writes:

Next to the tiny ideological bumps Republicans have obsessively smoothed from their record, Trump's profile of deviations is incomprehensibly vast. He has called himself pro-choice, endorsed single-payer health care, praised Hillary Clinton's performance as secretary of State, donated to Democrats, and called for a huge onetime tax on existing wealth. It must be galling for the party regulars to prostrate themselves helplessly before the base, purging any hint of independent thought, only to watch a formerly pro-choice, libertine if not liberal, Democratic donor waltz into the lead.

Trump's rise suggests that Republican voters are not quite as excited by the Republican field as elites hoped. There's little anecdotal evidence of Marco Rubio thrilling crowds in Iowa, or Rand Paul creating a libertarian earthquake in Iowa. Jeb Bush tends to poll second behind Trump, but there, too, his supporters tend to sound more pragmatic than inspired.

I agree with Bump. I don't think Donald Trump will win. The most recent CBS News poll found that while 24 percent of Republicans wanted Trump to win the nomination, 26 percent said Trump was the one candidate they absolutely didn't want to see win the nomination.

But this 2012-esque cycle wasn't supposed to repeat itself in 2016. This time was supposed to be different. The Republican field was supposed to be strong enough that the base was excited about candidates the party was proud of, rather than candidates the party was embarrassed by.

But the first debate is Thursday night, and Donald Trump will be at center stage because a large plurality of Republican voters say they would prefer him to any of the more credible candidates in the race. That might change as the primary wears on, but it wasn't ever supposed to happen in the first place.