Indeed, the pressure for the United States to respond at the end of the six-month window will not wait until that deadline arrives. Even before the ink on the deal was dry, lawmakers began urging new legislation that would slap Tehran with stricter sanctions next May if there is no deal to permanently end the alleged Iranian nuclear weapons program.

“I think you will see the Congress impose additional sanctions that won’t take place for six months with some conditions,” Sen. Lindsey Graham (R-S.C.) said on CNN as news of the interim deal was breaking. “If Iran meets certain conditions, they will never go into effect at all. But you will see the Congress have new sanctions that will be delayed for six months…we will define what success will look like before the sanctions can be waived in the future.”

“I will continue working with my colleagues to craft bipartisan legislation that will impose tough new economic sanctions if Iran undermines this interim accord or if the dismantlement of Iran’s nuclear infrastructure is not underway by the end of this six-month period,” said Sen. Mark Kirk (R-Ill.).

Among Democrats, House Minority Whip Steny Hoyer of Maryland also endorsed that approach Sunday.