The Republican race for president last week converged, suddenly and briefly, in Detroit. In the Fox theater, one of the nation's great 1920s movie palaces, the four remaining presidential candidates fought it out in the Fox News debate.
Earlier that day, Mitt Romney, who grew up in Detroit and suburban Bloomfield Hills when the Motor City was thriving, urged Republicans not to let Donald Trump win the party's nomination. John McCain joined in with words of support, and the views of the George Bushes can be taken for granted.
All this is a reversal of the usual pattern when the front-runner in the first dozen contests attracts widespread support. But such candidates have also been widely acceptable to a majority of primary voters and caucusgoers. Exit polls establish that Trump isn't.
At the debate Marco Rubio started off by pointing out that Trump has won only one-third 34 percent of the votes cast. He has finished below 40 percent in 12 of 15 contests. Rubio subjected Trump to the kind of bantering insults Trump has specialized in. Trump's sputtering interruptions were accompanied by whoops and hollers from the Fox Theater rafters, but were less effective than in the past.
Rubio's repeated emphasis on the scams perpetrated by Trump University and Ted Cruz's reminders that the fraud case which Trump says may take three years to resolve will be litigated during campaign season may have hit home.
Throughout the debate the most effective criticisms of Trump came from Ted Cruz. Again and again, in stentorian tones, he interwove the themes that Trump is not a conservative and cannot be trusted to follow through on his promised immigration crackdown. Rubio underlined this with adept criticism of Trump's reversal on H1-B visas.
John Kasich refrained from going after Trump which denied Trump rebuttal time required under debate rules. Instead Kasich made a strong case for himself and took solid conservative stands, switching from his previous answer on religious liberty. His performance seemed pitched to help him win Ohio.
In effect, if not in so many words, Trump's three remaining opponents seemed to be operating as a tag team, in line with the strategy Mitt Romney laid out.
In Florida Trump opponents should vote for Marco Rubio on March 15, thus denying Trump its 99 winner-take-all delegates. In Ohio they should vote that day for John Kasich, denying Trump the state's 66 winner-take-all delegates. In states like Louisiana, where Ted Cruz leads, they should vote for Cruz.
The purpose is to deny Trump the 1,237 delegates he needs for a majority at the convention in July. Trump advocates call this an establishment cabal. But a candidate who has broken every rule of decorum and substance, accusing a Republican president of lying the nation into war, is stopped from complaining about others not observing conventional rules.
Whether such tactical voting, common in parliamentary systems like Britain's, will work is unclear. There's little time between contests for reliable polling. But if a majority of Republican primary voters don't want Trump and would settle for any of the alternatives on offer, it could just work. There's nothing wrong with refusing to nominate a candidate opposed by a majority.
From Trump supporters I hear the argument that things have gone so badly over the last 15 years that a Trump presidency, for all its possible pitfalls, or the possibility that he could lose to Hillary Clinton, could not be worse.
But anyone who knows 20th century history knows that the downside risk for a society with the wrong leaders can be not just marginal but catastrophic. Trump's assurance that U.S. troops would follow his orders, even if contrary to law, should be chilling to anyone familiar with that history.
Near the end of the debate Ted Cruz made that point eloquently by citing Detroit and how, in his view, 50 years of liberal governance destroyed so much of a once thriving city.
I saw that destruction as an intern in the Detroit mayor's office during the 1967 riot and in repeated visits over the years afterwards, destruction wreaked in large part because of policies now advocated by Black Lives Matter and Hillary Clinton.
Rubio, Cruz and Kasich all lead Hillary Clinton in public polls. Donald Trump trails behind in virtually every one. Perhaps those now whooping and hollering for Trump will realize that the downside risks of a Trump nomination could be disastrous.