MACKINAC ISLAND, Mich. -

Michigan Republicans gathered Friday at historic Mackinac Island, united in their overwhelming desire to defeat Democratic President Barack Obama and U.S. Sen. Debbie Stabenow next year.

But splits were clear among the more than1,600 activists on issues ranging from a new bridge between Detroit and Canada to right-to-work laws and whether business owners should be required to check a federal database to make sure they don't hire illegal immigrants.

And the bumper stickers, signs and campaign literature being handed out as conference-goers walked from the ferries bringing them to the island to the sprawling Grand Hotel showed that the competition for votes among the Republicans running for the presidential and Senate nominations is heating up.

Former U.S. Rep. Pete Hoekstra held a news conference on the Grand Hotel porch with Gov. Rick Snyder to promote his Senate candidacy, while his top rival, charter schools official Clark Durant, went after Hoekstra in his own Detroit news conference earlier in the day.

The differences over favorite candidates is a given for the biennial conference. But the gathering also showed the party continues to struggle to keep its social conservatives and tea partiers in sync with its more moderate wing.

During a session with the state'stop GOP officials that included legislative leaders and Snyder, the audience asked pointed questions about what was happening with right-to-work legislation and the New International Bridge Crossing. Making union-heavy Michigan a right-to-work state -- where workers covered by union contracts aren't required to join unions or pay dues -- is a top goal of many tea party advocates and some GOP lawmakers.

"I understand the right-to-work issue and how people feel ... but it's not one of my priorities," Snyder said, repeating the same stance he has had since becoming governor in January. He added that "there are so many other things we can work on" that will do more to create jobs.

Senate Majority Leader Randy Richardville, who earlier this month said he wants to see right-to-work laws applied to school teachers and staff, said he has no current plans to take up broader right-to-work legislation, noting it's being "tabled at this point."

Many in the audience clearly still were skeptical about the need to build a bridge between Detroit and Canada separate from the Ambassador Bridge, whose owners say they should be allowed to add a second span.

Lt. Gov. Brian Calley, the administration's point man on getting legislation passed setting up an authority to oversee the building of the new bridge by a private contractor, said the need for it is clear, despite what the Ambassador Bridge owners have said in a series of ads.

Richardville and GOP House Speaker Jase Bolger said they both were on board with the governor because the legislation won't leave Michigan taxpayers on the hook for the bridge in any way. Richardville said he expects to bring up the bridge legislation for a vote in coming weeks.

The GOP participants began casting ballots Friday in a presidential straw poll being conducted by the National Journal. The two GOP presidential front-runners -- Texas Gov. Rick Perry and Michigan native Mitt Romney -- were to speak at different times to the conference on Saturday, but their supporters were decked out in campaign T-shirts and putting up campaign signs before either man was on the island.

Romney has said he's not participating in straw polls, but he's clearly a favorite in the only state he won in the 2008 Republican presidential contest. His father, George, headed American Motors and was Michigan's governor in the 1960s, a legacy that has benefited his son. But the younger Romney also has run afoul of some Michigan voters after opposing the 2009 federal bailout of General Motors and Chrysler. Romney said the automakers should have gone through a private bankruptcy without the federal aid.

Perry will be connecting with most Michigan Republicans for the first time since jumping into the presidential race six weeks ago, but he's contending with mounting opposition from some conservatives over his stands on immigration and immunizations against cervical cancer for girls.

Friday's session ended with a speech by Snyder, who pledged "to create an environment where the private sector will take off."

The governor planned to lead a bike ride around the island early Saturday morning before leaving for a weeklong trade trip to Japan, China and South Korea.