CLEARWATER, Florida (AP/WTSP) - Once a solidly Republican bastion of Northern snowbirds and conservative retirees, this stretch of coastal beach towns and sprawling subdivisions has moved toward the political middle.

Voters in this suburban St. Petersburg district backed former President George W. Bush in 2004 before narrowly supporting Barack Obama twice.

Now, the death of longtime Rep. Bill Young has made Florida's 13th District the proving ground for political arguments that both Republicans and Democrats hope will resonate with moderate voters in next year's midterm elections.

Democrats hope to use the special election to fill Young's seat to hammer Republicans over the government shutdown that far-right demands helped trigger. Republicans plan to blister Democrats over the disastrous rollout of Obama's health care law.

Monday marks the last day residents can register to vote or change their political party affiliation before the FL-13 primary and special elections.

The primary will be held on January 14. Republicans Kathleen Peters, David Jolly and Mark Bircher will be on the ballot.

The winner will then face Democrat Alex Sink in the general election on March 11.