WASHINGTON (AFP) -- Top U.S. Republicans gathered for a 2008 election dress rehearsal Saturday to gauge who has the mettle to lead the party after President George W. Bush finishes his second and last term.

The Republican Leadership Conference in Memphis, Tennessee, brought together the cream of the Republican crop, including many of those nurturing ideas of a 2008 White House run.

Delegates will make public the results of a straw poll, which many believe could serve as an early indication of who among half a dozen of so presidential hopefuls has the clout and charisma to rally the party.

The choice of Tennessee as the venue could be interpreted as a nod by the party establishment to Senate Majority Leader Bill Frist, who represents the southern state in Congress.

But few believe the home advantage alone will be enough to help the medical doctor-turned-politician eclipse potential rivals, who include maverick Arizona Senator John McCain, his youthful colleague from Virginia, George Allen, and Kansas Senator Sam Brownback, a darling of Christian conservatives.

Two moderate Republican governors Mitt Romney of Massachusetts and Mike Huckabee of Arkansas, also seen as strong potential contenders, mingled with delegates in a bid to build alliances outside their home states.

The Republican Party moves toward the 2008 presidential race with no political heir apparent. The U.S. constitution bars Bush from running for a third term, and his vice president, Richard Cheney, has repeatedly denied having higher political aspirations.

That forces top Republicans to act early to restructure their ranks to face the challenges of the future political season.