PALM HARBOR, Fla. -- Congressman Connie Mack is hoping to galvanize support for his Senate campaign with Republican activists.

Mack spoke to Florida's delegates to the Republican National Convention on Thursday and told them there are big differences between him and Democratic Sen. Bill Nelson.

Mack said Nelson has supported tax increases while he wants to cut taxes. And Mack said he wants to repeal President Barack Obama's health care overhaul, while Nelson voted for it.

And he stressed that the balance of power in the Senate is online.

Mack, however, won't be talking about Nelson or his Senate campaign Thursday night when he speaks at the convention. Mack's address will be part of the buildup to Republican presidential candidate Mitt Romney's speech.