President Trump's expected announcement next week on the fate of the Iran nuclear agreement could export to an already dysfunctional Congress a debate that continues to divide the White House and worry American allies.

Trump is expected to decertify the deal as early as Thursday by declaring the Joint Comprehensive Plan of Action, as it is formally known, in violation of U.S. interests.

In doing so, he will open a 60-day window for members of Congress to reimpose sanctions that were lifted by the Obama administration in exchange for restrictions on Iran's uranium enrichment and centrifuges. And while the move would please the Republicans who have called on Trump to end the nuclear deal by the Oct. 15 deadline, some members have indicated that they will not push sanctions legislation until they gauge Tehran's appetite for renegotiating problematic aspects of the JCPOA.

"I have no intention right now to introduce snapback sanctions legislation on Oct. 16th," Sen. Tom Cotton, a top critic of the Iran deal, said during an event this week at the Council on Foreign Relations. "That 60-day window is a relatively short period in which we can do what we already have the power to do, which is impose sanctions at any time."

The Arkansas Republican noted Trump could still revive all of the waived sanctions himself if he chose to do so and argued the brief period in which Congress is called upon to consider snapback sanctions will likely be insufficient for Trump to renegotiate the agreement. Ending waivers on those sanctions against Iran would amount to scrapping the JCPOA altogether.

"I'm not sure that 60 days is long enough to conduct the kind of coercive diplomacy I've mentioned. If it's obvious by the end of that 60-day period that the course of action I've recommended will not work, then perhaps we will have to reimpose sanctions then," Cotton said. "But I'm also willing to give the administration and our allies in Europe and the Middle East more time than just 60 days to try to get a better deal."

Other congressional Republicans have expressed doubts about taking steps that could unravel the JCPOA.

For example, Sen. Rand Paul, R-Ky., suggested in an interview with Politico late last month that too many critics of the deal had blurred the lines between violations of the agreement's provisions and aggressions that, while troubling, don't technically break with the deal.

Rep. Ed Royce, R-Calif., has urged the president to "enforce the hell" out of the existing agreement, and other GOP lawmakers have called on Trump to decertify the deal only in the event of clear material breach.

Trump's expected decision to decertify the deal may align him with populist aides who have left the White House and outside conservatives on whom he relied for advice during discussions about the deal over the past three months.

Sebastian Gorka, former adviser to Trump, said the president balked at the last recertification deadline in July, when most of the aides around Trump except former White House chief strategist Steve Bannon and himself successfully persuaded the president to leave the deal intact despite his objections.

"I was in the room the last time we recertified, I was there with the president, with Steve [Bannon], with H.R. McMaster, with Rex Tillerson, and with [Steve] Mnuchin. The president was not happy about recertification," Gorka told the Washington Examiner.

"I expect on the 12th, the president to keep to his expected behavior and to not recertify," Gorka added.

State Department officials and some senior West Wing aides will likely try to pressure Trump over the weekend and early next week into preserving the deal by arguing that European allies would object to any efforts to exit JCPOA, said a source familiar with the conversations.

Trump is not expected to take their advice, the source noted.

United Nations Ambassador Nikki Haley has among the few voices in the administration pushing Trump to scrap the deal, and she has emerged as a leading public critic of Iran's behavior.

The modifications Trump is expected to seek in the JCPOA if a renegotiation occurs include restrictions on Iran's ballistic missile program and more punishments for its support of terrorist-designated groups like Hezbollah.