The bill was supported heavily by vulnerable incumbents and signed into law by President Obama.

One of the most vulnerable incumbents in the country had escaped without an opponent.

Democrats have fewer vulnerable incumbents than Republicans and are well-positioned in several races for open seats.

As a result she is viewed by the Democrats as one of the most vulnerable Republican incumbents this year.

And there are, by most accounts, 6 to 10 vulnerable Democratic incumbents.

We haven't had many additions to our list of vulnerable incumbents.

Some of the Democrats' more vulnerable incumbents up for re-election have seemed to run away from the party message.

Both men are atop the list of the most vulnerable Democratic incumbents facing re-election next year.

Not only did the Republican politicians ensure that both went for the president's party, but they also shored up their vulnerable incumbents.

But Republicans thwarted that strategy by spacing out votes to allow their vulnerable incumbents to go home to campaign.