WASHINGTON — The State Department’s decision to grant a visa to Iran’s former president is sparking a rebellion among Republican members of Congress who seek a tougher line on the rogue country as it flaunts the latest U.N. deadline on its nuclear program.

Yesterday afternoon, the chairman of the House Subcommittee on the Middle East and Central Asia, Ileana Ros-Lehtinen, a Republican from Florida, began collecting signatures in Congress for a letter that she plans to send next week to Secretary of State Rice expressing “grave concerns” about the visa for Muhammad Khatemi that will allow him to speak before audiences at the National Cathedral, Harvard University, and the Council on American-Islamic Relations.

The letter says that allowing Mr. Khatemi to visit America “undermines U.S. national security interests with respect to Iran and the broader Middle East.” It also says permitting Mr. Khatemi’s “unrestricted travel through the United States runs contrary to U.S. priorities regarding homeland security.”

Not to be outdone, Senator Allen, a Republican of Virginia, facing a tough challenge to his seat this election cycle, tied the visa for Mr. Khatemi directly to Iran’s efforts to acquire nuclear weapons.

“The actions of the Iranian government under President Khatemi include the expenditure of billions of dollars on nuclear reactors and sophisticated weapons and the failure to implement reforms that are necessary for Iran to abide by its treaty obligations,” the senator wrote in a letter to Ms. Rice yesterday. “Granting this travel visa gives support to the current Iranian strategy of stalling action while it builds its nuclear capabilities and dividing the tentative coalition of states opposing Iran’s nuclear weapons program.”

Senator Brownback, a Republican from Kansas who authored the amendment in 2003 that created the first installment of federal funding for Iranian dissidents inside Iran, said yesterday that he also opposed the visa.

“Allowing a Khatemi visit signals that the United States is willing to ignore concerns about nuclear weapons, terrorism, and human rights — the very building blocks of our policy toward Iran,” he said in a statement provided from his office. “I urge the Administration to ensure that U.S. policy remains focused on defending our national interests and upholding our values.”

While the decision to grant what is known as a G-4 visa to the former Iranian president is not the most significant policy disagreement that Iran hawks have had in recent months with the Bush administration, its timing and the high profile public relations victory it gives the Islamic Republic has unleashed the ire of the president’s base this election year. The decision not only means that Mr. Khatemi will be meeting, among other luminaries, conservative bête noire Jimmy Carter, but that the State Department will afford a diplomatic security detail to guard the ex-president and his entourage.

The editor of National Review Online, Kathryn Jean Lopez, sensed the hawk’s opposition to the visa on Tuesday, when her website ran a symposium that included Senator Santorum, the third ranking Republican in the Senate, trashing the visa decision from the State Department.

On it, Mr. Santorum, who has cut his deficit against his Senate challenger in Pennsylvania to single digits, wrote that he should be granted a visa only if Iran allows their people to hear “free American voices.”

Mr. Santorum wrote: “We should insist, at a minimum, that the Iranian people can hear free American voices. Iran is frightened of freedom. They are jamming our radio and television broadcasts and tearing down television satellite dishes in all the major cities of the country. It seems only fair that we be able to speak to the Iranians suffering under a regime of which Muhammad Khatemi is an integral part.”

“Folks, and I hope not just conservatives, feel a sense of urgency when it comes to Iran, and it is key, of course, to the whole war against Islamofascism,” Ms. Lopez said in an email yesterday. “This administration needs to project a similar sense of urgency, and quickly, or increasing numbers of critical conservatives will be the least of its new problems. This White House — and well, State Department in a big way — has long had a clarity problem in this war, communications never its forte. This Khatemi visit certainly doesn’t help matters.”

Another contributor to National Review Online and scholar at the American Enterprise Institute, Michael Ledeen, summed up his frustration as follows: “This administration is doing terrible damage to itself by talking hawkishly and acting dovishly.This earns them the hatred of the doves for talking like hawks, and the contempt of the hawks for acting like doves.”