Two Democrats signed on to a Republican bill that would prevent any funds from being spent on prosecuting Guantánamo Bay suspects in U.S. federal court.

Reps. Jason Altmire (D-Pa.) and Mike McMahon (D-N.Y.) last week joined Rep. Pete King (R-N.Y.) and 16 other Republicans in sponsoring the legislation, which would deny the Justice Department any funds for trying Khalid Sheikh Mohammed and other suspected terrorists in federal civilian court.

In the weeks since GOP Sen. Scott Brown's historic election in Massachusetts, King said he believes support in the Democratic Caucus for President Barack Obama's detainee policies has eroded and predicted the measure would pass if Democratic leaders allow a floor vote on it.

"I have no doubt that if it comes to a vote on the House floor, it will pass," King said. "You cannot underestimate that impact of the election in Massachusetts, especially when so much of his [Brown's] messaging dealt with terrorism.

"A number of Democratic members and senators have come up to me and have thanked me for leading on this," he added.

Obama has not ruled out putting Mohammed on trial in New York City, but said Sunday that he is taking into account objections of the city's mayor and police commissioner.

New York City Mayor Michael Bloomberg originally supported the plan, but balked when costs for security reached an estimated $1 billion. He has since said holding the trials elsewhere, such as a military base, would be more feasible. The city's police commissioner, Ray Kelly, has said he was never briefed by the Justice Department about its plans to possibly hold the trials in lower Manhattan.

On Monday, Bloomberg said he wants assurance from the Obama administration that it will help pay for the additional security the city would need to provide for the trials to be held there.

Late last week, King and Rep. Frank Wolf (R-Va.), the ranking member on the subcommittee that funds the Justice Department, started circulating a letter addressed to Attorney General Eric Holder for House colleagues to sign. King's spokesman would not say exactly how many Democrats have signed on yet because the lawmaker plans to continue gathering signatures at the beginning of this week.

"In light of the growing opposition from New York's local and state leaders, Attorney General Holder is now reportedly venue shopping for a new location," King and Frank wrote. "This strategy is no less dangerous, costly or reckless than his decision to hold the trial in New York City."

Altmire and McMahon, two centrist Democrats, join Brooklyn's Rep. Nydia Velázquez (D) in opposing the administration's decision to hold Mohammed's trial in Manhattan. Late last year, Velázquez wrote Holder to say the trial would harm businesses, and, more recently, Sen. Dianne Feinstein (D-Calif.), who chairs the Senate Intelligence Committee, agreed with Bloomberg that Mohammed should not be tried in New York. New York's Democratic senators, Charles Schumer and Kirsten Gillibrand, have said they are receptive to alternative sites.

"From the Justice Department's first announcement about the KSM trial in November, I have stated that I thought the best course of action was to try these animals in a military tribunal," McMahon said in a statement. "If the administration is determined to have a civil trial, changing the venue of these trials is the only thing to do."

McMahon said he preferred the administration try the Sept. 11 terrorist suspects in military commissions at Guantánamo Bay and said he would oppose any use of taxpayer dollars to transport detainees to the U.S. for civil trials.

Altmire's office did not provide an explanation for his support by press time.

House Armed Services Committee Chairman Ike Skelton (D-Mo.) in late November sent a letter to Holder demanding that he appear before the committee to explain his decision to try Mohammed and four co-conspirators in federal court. He also wrote a letter to Holder and Defense Secretary Robert Gates suggesting that military tribunals would be a more appropriate venue to try accused terrorists. Skelton's opposition to the administration's decision about Mohammed and other detainee policies could help sway a large swath of Democrats, especially considering his senior position on a committee whose membership contains several centrist Democrats.

Other politically vulnerable Democrats would not say whether they support or oppose King's measure, another sign that support for the president's detainee plans is slipping in the House.

"I support the fastest way to bring these terrorists to justice," said two-term Rep. Patrick Murphy (D-Pa.), who declined to say whether he would vote for or against King's bill.

Rep. Dennis Cardoza, a Democrat from an agricultural district in California, also would not indicate whether he would support or oppose King's bill.

"I would have to see the exact language," he said in a brief interview.