(CNN) - John McCain says he is the Democrats' worst nightmare, but Mitt Romney begs to differ.
In a new Web ad released Friday, Romney's campaign is highlighting McCain's willingness to work across the aisle, and his strong relationships with some Senate Democrats.
It also features news reports that claim he considered joining John Kerry on the Democratic ticket in 2004. The Arizona senator has denied those reports.
The ad is the latest effort from the Romney campaign to portray McCain as too willing to work with Democrats, and comes just four days before the Florida Republican Primary - a contest that shuts out independent voters, whose support has been crucial to McCain's earlier victories in New Hampshire and South Carolina.
On Thursday, McCain's campaign released a Web ad noting the Arizona senator's name was frequently invoked at the CNN Democratic Debate, and claimed he was the “Democrats' worst nightmare” in a general election matchup.
– CNN Ticker Producer Alexander Mooney