WASHINGTON — It’s a done deal, yet opponents of the Iran nuclear agreement won’t go quietly.

The 60-day congressional review period has expired, and last week the State Department outlined its plan to put in place an accord that aims to prevent Iran from becoming nuclear-armed. Congress is poised to start cranking out legislation to reinstate sanctions or shore up what some lawmakers say is an ill-fated pact with a state supporter of terrorism.

Sen. Bob Corker, chairman of the Senate Foreign Relations Committee, has begun a series of hearings on the U.S. role and strategy in the Middle East that will examine the deal’s implications.

“It’s going to take a while. It’s a very substantive issue,” said Corker, R-Tenn., who opposed the deal. “It will be a complex piece of legislation.”

Confronted by Democratic opposition, Corker said, “Let’s face it. It’s going to be one bite at the apple.”

Republicans failed when Senate Democrats banded together to block a resolution of disapproval from ever reaching President Obama. On Thursday, the State Department said Obama would start issuing waivers Oct. 18 so the U.S. is ready to grant sanctions relief if Tehran meets its obligations to curb its nuclear program.

Iran has to uninstall thousands of centrifuges at its facility at Natanz, its main site for enriching uranium; convert an underground nuclear site at Fordo into a research facility; and redesign its heavy water reactor at Arak so it cannot produce weapons-grade plutonium. Iran also has to ship its stockpile of enriched uranium abroad, and comply with an International Atomic Energy Agency investigation into its past nuclear weapons work.

It’s not clear how long that will take.

If the IAEA finds that Iran has complied with key nuclear commitments, then sanctions imposed by the U.S., United Nations and Europe on Iran’s energy, financial, shipping, auto and other sectors are to be suspended.

One idea being discussed in Congress calls for shoring up oversight of Iran’s compliance. Another measure would reauthorize the Iran Sanctions Act.

Other legislation would strengthen security for Israel and for U.S. allies in the Persian Gulf.