WASHINGTON — Two Arkansas Republicans are urging House leaders to insist that any spending bills passed this fall contain no money for President Obama’s signature health care law.

Reps. Tim Griffin, R-Little Rock, and Rick Crawford, R-Jonesboro, joined 78 colleagues on a letter to House Speaker John Boehner and Majority Leader Eric Cantor supporting a showdown this fall over the Affordable Care Act.

"We urge you to affirmatively de-fund the implementation and enforcement of Obamacare in any relevant appropriations bill brought to the House floor … including any continuing appropriations bill," they wrote.

Democrats were quick to criticize the letter after it was made public Thursday, emphasizing that it could lead to a shutdown of government services when the new fiscal year begins Oct. 1.

In separate press releases, the Democratic Congressional Campaign Committee claimed that Griffin and Cotton had signed onto an "irresponsible, reckless and dangerous game of brinksmanship."

Crawford and Griffin said that they are not calling for a government shutdown and that the letter does not threaten one.

"The letter does not advocate for a government shutdown: You won’t find those words anywhere in the letter, just like you can’t find any of the lower costs or economic benefits President Obama and Nancy Pelosi attribute to Obamacare," Griffin said.

"I believe that rushing ahead with $1.3 trillion in new entitlement spending in the middle of a debt crisis is irresponsible and the letter I signed expresses my desire for House leadership to consider using the appropriations process as a mechanism to move toward stopping this madness," Crawford said.

While Republicans are united in wanting to repeal the federal health care reform law, they are divided on the defunding strategy.

Sen. John Boozman, R-Ark., suggested earlier this week that it is "not a winnable strategy" because a government shutdown would cause severe harm to the economy and would not stop federal health care reform.

Rep. Mark Meadows, R-N.C., who organized the letter, said that defunding Obamacare by the end of September is key because enrollment begins Oct. 1 in state-based health care exchanges — a major component of the health reform law.

"The American people are with us on this particular issue," Meadows said during an interview Thursday with conservative radio host Mike Huckabee.

Reps. Steve Womack, R-Rogers, and Tom Cotton, R-Dardanelle, did not sign the letter. Cotton, who is running for Senate in 2014, has come under daily criticism this week from Democrats seeking to tie Cotton to any damage that could result from a potential government shutdown.

Congress has not enacted appropriations bills needed to keep the government operating beyond the end of the current fiscal year on Sept. 30. As in recent years, they likely will turn to a continuing resolution that would temporarily fund the government.