McCain came close.
What no one knew was that Mike Huckabee would prove even stronger than expected in the South, apparently foreclosing Romney's chances of ever overtaking McCain.
With returns in delegate-rich California still unclear as this is written, a final verdict is elusive. But it is clear that McCain is now the undisputed frontrunner and presumptive nominee.
Tuesday also proved that Huckabee is the Achilles heel of the Romney campaign, denying the former Massachusetts governor a share of his natural constituency: evangelical Christian "values" voters who would be expected to support Romney were Huckabee not in the race.
Huckabee captured West Virginia, then went on to claim Alabama, Georgia, Tennessee and his home state of Arkansas.
That run through the South is a symbol of the dilemma for the Romney campaign. Throughout the primaries, it has been "Close, but no cigar." It happened in Iowa, New Hampshire, South Carolina and Florida. And the spoiler has been Huckabee.
In Utah, of course, the result was predictable from the moment Romney entered the race. He won the Beehive State primary running away. But the corrosive religious politics which guaranteed Romney victory in Mormon Utah also guaranteed him problems in other states, particularly in the South and Midwest, where evangelical Christians are a major Republican voting bloc. So long as Huckabee, an ordained Baptist minister, remains in the race, he bleeds votes from Romney.
Romney won mostly small states in the North and West - Minnesota, North Dakota, Colorado and Montana - plus Utah and his home state of Massachusetts.
But if two candidates cause an election to turn on religion, what does that mean for the future of the Republican Party? Huckabee cannot win the Republican nomination, but he probably has given it to McCain. Still, it is impossible to imagine the evangelical base of the party coming out strongly for the maverick McCain in November, unless Huckabee were on the ticket as the vice presidential candidate.
The Republicans played with fire when they used religion to build the foundation of the modern party. It remains to be seen if that fire could consume them.