Sen. Mike Lee of Utah and Sen. Ted Cruz of Texas (AP Photo)

(CNSNews.com) - Republican Senators Ted Cruz of Texas, Mike Lee of Utah, Jeff Sessions of Alabama, Pat Roberts of Kansas, Mike Crapo of Idaho, and David Vitter of Louisiana sent a letter to lame-duck Senate Majority Leader Harry Reid of Nevada today saying that if President Obama takes unilateral action to grant amnesty to illegal aliens it "will create a constitutional crisis."

The senators told Reid that they would assist him in enacting a measure to stop Obama from unilaterally granting an amnesty, but that if Reid lets Obama go forward with such an amnesty they "would use all procedural means necessary" to make the Senate focus on the constitutional crisis they say that this "lawless amnesty" would create.

On Dec. 11, the continuing resolution now funding the government will expire. Before that date, both Houses of Congress will need to approve a new continuing resolution to fund the government beyond that date.

If the CR does not permit the Executive Branch to spend money on some action, the Executive Branch cannot take that action.

"We write to express our alarm with President Obama's announced intention to take unilateral executive action by the end of this year to lawlessly grant amnesty to immigrants who have entered the country illegally," the senators wrote Reid.

"The Supreme Court has recognized that 'over no conceivable subject is the power of Congress more complete' than its power over immigration," the senators said. "Therefore, President Obama will be exercising powers properly belonging to Congress if he makes good his threat.

"This will create a constitutional crisis that demands action by Congress to restore the separation of powers," the senators told Reid.

"As majority leader of the Senate, you have the responsibility of not only representing the citizens of your state, but also of protecting the Constitution through vigilant exercise of the checks and balances provided under the Constitution," wrote Cruz, Lee, Sessions, Roberts, Crapo and Vitter.

"Therefore, we write to offer our full assistance in ensuring expeditious Senate debate and passage for a measure that preserves the power of Congress by blocking any action the president may take to violate the Constitution and unilaterally grant amnesty," the senators said.

"[H]owever," they continued, "should you decline to defend the Senate and the Constitution from executive overreach, the undersigned senators will use all procedural means necessary to return the Senate's focus during the lame duck session to resolving the constitutional crisis created by President Obama's lawless amnesty."