With President Trump declining to certify that the Iran deal is in the best interest of the United States, Congress will be faced with the decision of whether to take new steps to counter Iranian aggression. There will be plenty of time in the coming months to debate the details of any such legislation, but as Congress considers what to do, lawmakers should operate under the premise that they are under no obligations to honor former President Barack Obama's promises to Iran.

Any action Congress takes to counter Iran will trigger outrage among supporters of the lousy deal, who will charge that undermining the deal would send a message to the world that the U.S. no longer honors its agreements and commitments. In reality, any such international blowback should be blamed on one person and one person only: Barack Obama.

The Iran Deal does not have the weight of a treaty that was negotiated by the executive branch and ratified by two-thirds of the Congress, as required by the U.S. Constitution. Because Obama lacked the support to make it a treaty, he negotiated it as an executive agreement. The benefit was that it allowed him to secure the deal, but the drawback was it left it open for revision or termination. He was aware of all of this, and went ahead with his deal anyway.

Congressional Republicans were emphatic while the deal was being negotiated that anything negotiated by the Obama administration without the approval of Congress should effectively be seen as just that -- Obama policy.

In fact, in a 2015 open letter that caused a fit among liberals, 47 Senators led by Sen. Tom Cotton, R-Ark., put the Iranian regime on notice that they should not assume any deal supported by the Obama administration would survive a new administration.

The letter read that, "we will consider any agreement regarding your nuclear-weapons program that is not approved by the Congress as nothing more than an executive agreement between President Obama and Ayatollah Khamenei. The next president could revoke such an executive agreement with the stroke of a pen and future Congresses could modify the terms of the agreement at any time."

It couldn't have been more clear. Obama made his decision to move ahead with the deal with the full knowledge that he was making promises that he could not bind future Congress's or presidents to -- and he pressed ahead, even as bipartisan majorities in both chambers of Congress opposed it. He knew his promises were being made on a shaky foundation, and he put U.S. credibility on the line anyway.

His calculation was that once the shoved the deal down the throats of Congress, that future lawmakers and presidents would be too scared about the consequences to touch the deal, or to impose new sanctions that could trigger its unraveling.

So the question really facing Congress right now is whether they should do what's in the national security interest of the U.S., or allow themselves to be handcuffed by promises made by a prior administration over objections of Congress. Will lawmakers prove as gutless as Obama assumed?