Democrats sought funds on Wednesday to help defend vulnerable House lawmakers who helped pass healthcare legislation on Sunday.

Democratic National Committee (DNC) Chairman Tim Kaine wrote subscribers of the party's email list to make the party's first formal appeal for donations since the bill's passage to fend off GOP offensives against House members.

"On Sunday night, many Congressional Democrats in tough districts cast courageous votes for health reform -- even though they knew that insurance companies and their Republican allies would retaliate immediately," Kaine wrote to party supporters.

"But we're ready to do what it takes to defend the heroes who made health reform possible," the former Virginia governor added. "These are the men and women who stood with us and the President to make good on a promise that our Party has fought to deliver for a century. And we will not leave them hanging out to dry."

A number of potentially vulnerable House Democrats were among the 219 who voted to support healthcare legislation on Sunday. 34 Democratic lawmakers broke ranks to oppose it.

In the aftermath of the vote, the Republican National Committee (RNC) has launched a "Fire Nancy Pelosi" campaign targeting the Democratic speaker of the House, which, according to an online tally, has raised almost $1.4 million since Sunday evening.

The DNC has raked in roughly $2 million since the bill's passage on its own before Kaine's appeal.