With the Senate set to begin full debate this week on a bipartisan bill to give Congress the authority to review and potentially reject any Iran nuclear deal, some members are being warned about pushing amendments that change the bipartisan legislation and nix its support.
"Anybody who monkeys with this bill is going to run into a buzz saw," Sen. Lindsey Graham, R-S.C., warned ahead of the floor debate.
And Sen. Bob Menendez, D-N.J., is urging fellow senators to stick with the plan that recently emerged from the Senate Foreign Relations Committee.
The high-profile debate comes as negotiators from the United States and five other countries try to reach a final deal with Iran by June 30 to curb the country's nuclear-enrichment program, in exchange for relief from sanctions choking its economy.
The parties will meet again this week on the sidelines of a U.N. conference in New York.