Denver ? Hoping to use the volatile issue of illegal immigration to avert a November election disaster, Republican candidates across the country increasingly are attacking their Democratic opponents on the subject.

But mindful of a possible voter backlash, they are attempting to do so without seeming intolerant or divisive.

In Pennsylvania, U.S. Sen. Rick Santorum has launched an ad accusing his challenger of favoring amnesty for people in the country illegally and giving them “preference over American workers.” Rep. Bob Beauprez criticizes his Democratic opponent in the Colorado governor’s race for supporting state benefits for illegals. In the Chicago suburbs, congressional hopeful David McSweeney is attacking Democratic incumbent Melissa Bean on immigration – even though she voted in favor of the crackdown bill that passed the House last December.

Immigration is a tricky issue for Republicans, and there are deep divisions in the party over what policy and strategy to pursue. Many blame former California Gov. Pete Wilson’s backing in 1994 of anti-illegal immigrant Prop. 187 for alienating Hispanics nationwide.

In California, it sparked a wave of Hispanic political activism that hurt the GOP’s political standing – a blow from which the party has yet to fully recover.

Still, Republican strategists have “made a decision that, whatever the risk, this is simply a very bad year and the issue is too hot not to put it in the quiver,” said Floyd Ciruli, a Denver-based independent pollster.

The stepped-up Republican assault comes as House GOP leaders began a nationwide series of hearings bashing the Senate’s bipartisan immigration bill, which they have branded the “Kennedy-Reid” bill – focusing on two prominent Democratic supporters while ignoring the lead Republican sponsor, Sen. John McCain of Arizona.

The linguistic dodge reflects the wide split in the GOP over two competing approaches to immigration. President Bush and pro-business Republicans favor a guest-worker program and pathway to citizenship contained in a bill approved by the Senate.

The president reiterated his support of a guest-worker program Friday during a news conference in Chicago. “To enforce this border, we’ve got to have a rational way that recognizes there are people sneaking across to do work Americans aren’t doing,” he said.

But hard-liners in the party back the tough measures contained in the House’s enforcement-only legislation and fiercely oppose the president’s guest-worker approach.

The official GOP position is that the party will not use immigration as a political bludgeon against Democrats. Karl Rove, the president’s chief political adviser, has made courting Hispanics a priority throughout his years in the White House and has avoided the harsh rhetoric used to rally partisans on other issues.