Putting Florida at the forefront of the fight over healthcare reform, the national Republican Party on Tuesday dispatched two top senators to blast President Barack Obama's agenda at a Hialeah hospital and launched a television ad promising to "protect seniors."

Former presidential nominee John McCain of Arizona and Senate Republican Leader Mitch McConnell of Kentucky joined Florida Sen. Mel Martinez at a polite, closed-door forum with staff at Palmetto General Hospital. Following stops in Missouri and North Carolina, it was the third joint appearance by McCain and McConnell on a road trip aimed at presenting the party's closing arguments before Congress takes up sweeping healthcare legislation next week.

"We have to make sure that in doing so we do not destroy this healthcare system," Martinez said.

Outside the meeting, about 20 AFL-CIO workers rallied in favor of reform and carried signs that said, "Healthcare can't wait." Florida Democratic leaders also organized a phone call with reporters to denounce the GOP ad, which is airing on national cable stations and in the northern Florida district represented by a moderate Democrat, Allen Boyd of Monticello.

"They're trying to put fear in seniors' hearts and scare them into believing they will lose benefits they have now, and nothing could be farther from the truth," said U.S. Rep. Debbie Wasserman Schultz of Weston, who said the legislation would expand coverage for prescription drugs and lower insurance costs.

A recent Quinnipiac University poll showed support for Obama hitting a new low in Florida amid concerns that healthcare reform will drag down the quality of care and inflate the national debt. Florida offers fertile ground for Republican attacks because of the state's large population of healthcare- dependent seniors.

"Seniors in Florida have been very vocal in their opposition to the Demo- crats' government-run healthcare experiment," said Republican National Committee spokeswoman Sara Sendek.

In contrast to the rowdy confrontations that have disrupted some public forums on healthcare, no one talked out of turn at the invitation-only event in Hialeah. Most people in the audience wore suits. McConnell's call to protect doctors from lawsuits drew steady applause.

"We're talking about a very large restructuring of one-sixth of our gross national product, and that's why we're getting a reaction the likes of which we've never seen," said McCain, who said he favors a more targeted approach that would help ill people who have been rejected by insurers.

Martinez acknowledged the event would be his last in Florida before he steps down next week. Gov. Charlie Crist has appointed his former chief of staff, George LeMieux, to serve the remaining 16 months of the term.

LeMieux was scheduled to meet with Martinez and discuss committee assignments with McCain and McConnell in Miami on Tuesday. He said last week that "there's a lot that concerns me'' in the Democrat-backed healthcare bills.

In the ad released by the Republican national party, chairman Michael Steele calls for a "seniors' bill of rights'' and suggests that Democratic reforms will "ration healthcare based on age'' and allow government to interfere in end-of-life decisions. Wasserman Schultz called it a ‘‘seniors' bill of lies."

AARP also knocked the ad in a press release that said, "We are pleased nothing in the bills that have been proposed would bring about the scenarios the RNC is con- cerned about."

In the call with reporters, Edward Coyle of the Alliance for Retired Americans, a liberal, union-affiliated group, acknowl- edged that healthcare reform supporters had been initially "outstrateg- ized," but now were com- mitted to making making sure their voices were as loud as their opponents. ‘‘The tide has turned," said Wasserman Schultz.

But the meager turnout at Tuesday's rally reflected the challenges facing supporters of the Democrat-backed legislation. Union members and Democratic activists are planning another rally at Democratic U.S. Rep. Kendrick Meek's town hall meeting Thursday in Miami.

In one of the only local forums to pair up leaders from both parties, Democratic Rep. Alcee Hastings of Miramar and Republican congressional candidates Allen West and Ed Lynch are participating in an event Thursday organized by the Palm Beach Republican Party.

Herald/Times writer Mary Ellen Klas contributed to this report.