Senate Majority Leader Mitch McConnell takes the podium as he and U.S. President Donald Trump speak to the media together in the Rose Garden of the White House in Washington, U.S., October 16, 2017.

Five years ago, political scholars Norman Ornstein and Thomas Mann published an article with this bracing conclusion: "Let's just say it: The Republicans are the Problem."

That conclusion angered Republican politicians. It came during their furious 2012 campaign to recapture the U.S. Senate, defeat President Barack Obama and put Mitt Romney in the White House.

Today, Republicans have won both houses of Congress, made Donald Trump president and created an all-GOP government. The stunning result: More and more Republicans themselves voice the same conclusions as Ornstein and Mann about what their party has become.

On Tuesday, it was Tennessee Sen. Bob Corker, who won re-election in that 2012 campaign. Now chairman of the Senate Foreign Relations Committee, Corker characterized the Republican president as a danger to U.S. national security.

Hours later, Sen. Jeff Flake accused Trump of leading Americans toward a future as "fearful, backward-looking people." The Arizona senator, who won his seat in 2012 and won't run again, challenged GOP colleagues to resist indecency and dishonesty from the White House.

Last week, the previous Republican president, George W. Bush, condemned Trump-era "bigotry … conspiracy theories and outright fabrication." The 2008 Republican presidential nominee, Sen. John McCain, ripped a "half-baked, spurious nationalism cooked up by people who would rather find scapegoats than solve problems."

Two months ago, Romney, who lost to incumbent Obama in 2012, called on Trump to apologize for remarks about a white supremacist rally in Charlottesville, Virginia. He said the Republican president had "caused racists to rejoice, minorities to weep, and the vast heart of America to mourn."

Instead of apologizing, Trump repeated his remarks.

The seeds of what those Republican leaders denounced were planted decades ago. Beginning in the 1960s, Republicans seized on turmoil over civil rights, cultural ferment and the Vietnam War to draw conservative whites in the South and elsewhere into a national majority coalition.

Since then, the party has grown increasingly homogeneous as the country has grown more diverse. Diversity and rising social tolerance among younger and better-educated voters helped Democrats win presidential elections again, with Bill Clinton and Obama.

At the same time, Republicans have grown dependent on older, blue-collar white conservatives aggrieved by declining economic prospects and cultural change. Before those voters propelled Trump to the Republican nomination, they pushed lawmakers toward the behavior that Ornstein and Mann described when they foreshadowed today's GOP crisis.

"The GOP has become an insurgent outlier in American politics," they wrote in "It's Even Worse Than It Looks," the book from which their 2012 article was drawn. "It is ideologically extreme; contemptuous of the inherited social and economic policy regime; scornful of compromise; unmoved by conventional understanding of facts, evidence and science; and dismissive of the legitimacy of its political opposition."

They concluded, "When one party moves this far from the mainstream, it makes it nearly impossible for the political system to deal constructively with the country's challenges."

This year's failure of an all-GOP government to fulfill promises to repeal and replace Obamacare demonstrated the point. The irony is that, as more Republicans speak out in agreement, Ornstein and Mann see signs of change.

In their new book with liberal commentator E.J. Dionne Jr., they cite growing resistance to Trump across the political spectrum. It can lead, they argue, "to rebuilding the more responsible, forward-looking center-right party that the country needs."

"The popular mobilization and national soul-searching he has aroused could be the occasion for an era of democratic renewal," they write in "One Nation After Trump."

Flake offered a hint on Wednesday after his dramatic speech on the Senate floor. In an interview on MSNBC, he repeated a formulation Obama used when he struggled with bitter and implacable Republican opposition.

"At some point," the Republican senator said, "this fever will break."