New York's Kennedy Airport is one of five where travelers from west Africa are being screened for Ebola. (Craig Ruttle/AP)

Worried about the political fallout from the Ebola outbreak, vulnerable Senate Democrats are declaring their support for a U.S. travel ban from the afflicted countries in west Africa.

In multiple cases, the Democrats are shifting from their earlier positions on the question, despite arguments from senior U.S. medical officials and the White House that stiff restrictions would only make it harder to prevent an infected person from entering the country. Senator Jeanne Shaheen of New Hampshire joined the crowd on Monday night, saying through a spokesman that she "strongly supports any and all effective measures to keep Americans safe including travel bans if they would work." Shaheen said last week she didn't think a travel ban makes sense, but she is facing heavy criticism from her Republican opponent, former Senator Scott Brown, on the issue. Under pressure from Republicans, Senator Kay Hagan came out in support of a ban late last week, and Senators Mark Pryor and Mark Udall have also called for travel restrictions.

Even Governor Andrew Cuomo of New York, a Democrat who is not in a particularly close race, changed his stance on Monday and said the government should "seriously consider" a ban.

The question has quickly become a classic pre-election litmus test in that it may well be a moot point by the time Congress has the chance to do anything about it. Several GOP lawmakers, including Senator Marco Rubio of Florida, have announced plans to introduce legislation when Congress returns to session, but that won't happen until the brief lame-duck period a month from now. After that, the House and Senate will break for nearly another month until the 114th Congress begins in January.

Another key indicator that the calls are more political than policy-focused? They are emanating much more loudly from candidates on the campaign trail than from the party leaders on Capitol Hill.

Some lawmakers have also stumbled over the meaning of a travel ban. There are currently no direct flights to the U.S. from Liberia, Sierra Leone, and Guinea–the three west African nations where the Ebola outbreak is occurring–so any restrictions would have to be enforced at connecting airports in Europe. Traveler screenings have already been implemented at five U.S. airports, but they likely would have to be continued anyway to catch passengers who fly to Europe, but do not immediately transfer to a U.S.-bound flight.

With that in mind, as The New York Times noted Tuesday, GOP leaders have subtly shifted their focus from an outright travel ban to demanding tighter airport screenings and the creation of "no-fly" lists to make sure people who have been exposed to Ebola do not board flights.

At heart, the wavering Democrats are simply trying to find another way to distance themselves from the unpopular President Obama and his administration's increasingly criticized response to Ebola. And on this front, the president is not making it easy for them. Speaking to Al Sharpton on the radio Monday, Obama called the Senate Democrats in the toughest re-election races "strong allies and supporters" who had "supported my agenda in Congress."

Obama's comments amount to a tightening of the leash on the run-away members of his party. As David A. Graham has argued, they may well be a deliberate attempt to drive up turnout among the liberal Democratic base, particularly considering Sharpton's likely audience. But if so, the comments don't appear to be coordinated with senators like Hagan, Pryor, and Mark Begich. They continue to sprint as fast away from the president as possible, with the Ebola travel ban serving as just the latest example.