John McCain's string of cross-country victories put him on the brink of being unstoppable — and showed his appeal across all segments of the Republican Party.
McCain had Mitt Romney sought to stretch out the bruising race for weeks more, although NBC News reported that an official in his campaign said that Wednesday would be a day of "frank discussion" and that a visit to Kansas ahead of the GOP caucuses in Kansas was in doubt.
Meanwhile, Mike Huckabee competed for relevancy.
"We've won some of the biggest states in the country. We have won primaries in the West, the South, the Midwest, and the Northeast," McCain said. "And although I've never minded the role of the underdog ... we must get used to the idea that we are the Republican Party front-runner for the nomination of president of the United States. And I don't really mind it one bit."
He scored big victories in winner-take-all New York, New Jersey, Connecticut, Arizona and Delaware and won in California, Illinois and Oklahoma. In one of the most hard-fought contests, McCain apparently edged out his rivals to seize Missouri, also a winner-take-all and one Romney had pursued fiercely.
With 516 total delegates to 207 for Romney and 142 for Huckabee, the Arizona senator was racking up enough delegates in Super Tuesday's coast-to-coast voting to place him within reach of the Republican presidential nomination that eluded him eight years ago. It takes 1,191 to win the nomination at this summer's convention in St. Paul, Minn.
His victories were fueled by a number of diverse voting groups, including moderates, independents, men, older voters, veterans and Hispanics.
"One thing that's clear is this campaign's going on!" Romney said, undeterred by the deficit — and the fact that he won only caucuses in North Dakota, Montana and Minnesota as well as primaries in Massachusetts, his home state, and Utah, whose huge Mormon population was friendly to one of their own.
Strong showings for Huckabee in South
Huckabee, too, promised to press on — and tried to edge out Romney. Christian evangelicals contributed to the former Arkansas governor's strong showings in the South and helped cut into Romney's standing among conservatives.
"I've got to say that Mitt Romney was right about one thing — this is a two man race. He was just wrong about who the other man in the race was. It's me, not him," Huckabee told The Associated Press, emboldened by wins in West Virginia, Alabama, Tennessee, Georgia and Arkansas.
The trio, and Texas Rep. Ron Paul, fought Tuesday for more than 1,000 delegates at stake in primaries and caucuses in 21 states.
Going into Tuesday's voting, McCain and Romney were best positioned to win the nomination, and the cross-country contests tested the reach of both to the GOP's ideological segments.
McCain led among Republicans who called themselves moderates, while Romney had an edge among Republicans who said they are conservatives, according to preliminary results of exit polling in 16 states for the AP and television networks. But, in a sign of progress for McCain, the two tied among self-described Republicans. McCain, as expected, had the advantage among independents who voted in GOP primaries.
On candidate qualities, McCain got strong support from people valuing experience, leadership and the ability to beat Democrats in a general election. He was widely considered the best Republican to be commander in chief. Romney, for his part, dominated among people looking for a candidate who shared their values and those wanting a hard line against illegal immigrants.
McCain, the Arizona senator and Vietnam prisoner of war, wanted to end the contest and seize the party prize he lost in 2000. He had a jolt of momentum behind him after his once-crippled candidacy rebounded last month to string together a series of wins in New Hampshire, South Carolina and Florida.
Resistance on the radio
But with a reputation for bucking the party, McCain faced intense resistance from high-profile conservative radio hosts with large audiences among the GOP rank-and-file.
"I am convinced Senator McCain is not a conservative, and in fact has gone out of his way to stick his thumb in the eyes of those who are," James Dobson, the founder of Focus on the Family, said Tuesday in a statement to a conservative talk show host who read it on the air. He said he would not vote for McCain "as a matter of conscience," and described McCain as someone with a "legendary temper" who "often uses foul and obscene language." Dobson said he would sit out the general election if McCain was the GOP nominee.
Romney, the former Massachusetts governor and business executive, previously won in hard-fought Michigan, his native state, as well as scarcely contested Nevada, Wyoming and Maine. He was out to prove he could win a hotly contested state where he didn't have generational links and hoped to grab enough delegates to keep him competitive with McCain heading into the next round of contests Feb. 9 in Louisiana and Kansas, and Feb. 12 in Virginia, Maryland and Washington, D.C.
Romney was counting on benefiting from conservative backlash against McCain.
The history-making possibilities were high. McCain, age 71, would be the country's oldest first-term president when inaugurated, while Romney would be the nation's first Mormon president.