Last fall, Michigan Gov. John Engler promised Republicans that his state's primary would be the "firewall" to opponents of presidential candidate George W. Bush.

It was a promise that Engler could not deliver.

Arizona Sen. John S. McCain notched a narrow but significant win in the Michigan primary last night. He also won handily in his home state of Arizona.

With majority of the precincts reporting in Michigan, McCain led Bush, 50 percent to 44 percent. Former ambassador Alan L. Keyes '72 registered 5 percent in the state.

A little startled by the defeat, Bush, who was campaigning in Missouri, said, "This is a marathon, and I'm going to be in it all the way to the end--and some primaries you win and sometimes you don't."

But pollster John Zogby, who has proved his credibility to the campaigns by his accurate tracking polls, said McCain's victory proves the senator can create enthusiasm among voters in a populous, diverse state.

"It's a whole new ballgame," Zogby said.

McCain can thank a huge turnout in the state--more than 1,000,000 voters--for his victory.

Exit polls show that nearly 51 percent of primary voters were either Democrats or Independents. Eighty-two percent of those voters chose McCain.

Bush gained the vote of a large majority of the state's Republican voters, but since Republicans comprised only a plurality of voters in the primary, Bush did not have enough support to win.

Even before the polls closed last night, Engler and other prominent Bush supporters sought to downplay McCain's win.

"This is the first time in American politics that we've had a Republican candidate seeking hard-core Democrats to come into our primary," he told reporters.

Bush charged that non-Republicans had stolen the primary for McCain.

No matter where his support came from, McCain conceded yesterday that his campaign was in a must-win situation.

"Every day is do or die," he said while voting his home state of Arizona. "We're a high-wire act and an insurgency campaign."