WASHINGTON -- The Egyptian government's move to arrest dozens of members of the Muslim Brotherhood, including its leader, Mohamed Badie, and his influential deputy, Khairat el-Shater, could test the cautious response from the United States to the ouster of Mohamed Morsi, the country's first democratically elected president, a senior administration official said.
While officials, including President Obama, have pointedly avoided referring to the military's takeover as a "coup," they warned that a political crackdown could imperil American military aid to Egypt. Hours after the nation's military announced that it had detained the ousted leader, Mr. Obama released a carefully worded statement calling on the military to "move quickly and responsibly to return full authority back to a democratically elected civilian government as soon as possible" and "avoid any arbitrary arrests of President Morsi and his supporters."
Only subtly, in the next line of his statement, did Mr. Obama invoke America's lever in the volatile situation.
"Given today's developments," Mr. Obama said, "I have also directed the relevant departments and agencies to review the implications under U.S. law for our assistance to the government of Egypt."
Mr. Obama's statement, the senior administration official said on Wednesday, was calculated to give the Egyptian military a window to stabilize the country. But if it used the takeover as a pretext to further crack down on Mr. Morsi or the Muslim Brotherhood, he said, the president would use harsher words and raise the threat of cutting off aid.
The United States provides $1.3 billion a year in military aid to Egypt, making it the second-largest recipient of American foreign assistance, after Israel. However, the military's actions could put that at risk, said the chairman of the Joint Chiefs of Staff, Gen. Martin E. Dempsey.
"If this were to be seen as a coup, then it would limit our ability to have the kind of relationship we think we need with the Egyptian armed forces," General Dempsey said in an interview that was taped Wednesday to be aired Sunday on "State of the Union" on CNN.
General Dempsey noted that there were "laws that bind us on how we deal with these kinds of situations." Legislation requires the United States to cut off financial assistance to nations where democratic governments are overthrown by the military or where the armed forces otherwise violate human rights.
In recent days, but especially after Mr. Morsi delivered a defiant televised speech Monday night, the White House had concluded that military intervention was likely. While far from ideal, the administration official said, the military's involvement could avoid a spiral into violence that seemed possible given the unwillingness of Mr. Morsi or his opponents to negotiate.
General Dempsey telephoned his counterpart in Egypt, Lt. Gen. Sedky Sobhi, the military's chief of staff, on Monday morning.
"I wanted to hear, get their assurance that they would protect our U.S. citizens -- and they will," General Dempsey said. "I wanted to encourage them to protect all the Egyptian people, not to take sides in any particular issue, and to ensure that they were a part of the resolution of this, but in their proper role as a military, which is to ensure stability but not try to influence the outcome."
Members of Congress have also focused on the question of aid in their public statements after the ouster of Mr. Morsi.
Senator Patrick J. Leahy, Democrat of Vermont, who leads a Senate subpanel on foreign aid spending, was critical of Mr. Morsi's governance but warned the Egyptian military of the risk in delaying a return to a democratically elected government.
"Our law is clear: U.S. aid is cut off when a democratically elected government is deposed by military coup or decree," Mr. Leahy said in a statement on Wednesday. "As we work on the new budget, my committee also will review future aid to the Egyptian government as we wait for a clearer picture."
In Washington on Thursday, President Obama met with his national security team in the Situation Room to discuss the events, while Secretary of State John Kerry and others called a variety of Egyptian officials urging them to restore democracy.
"Members of the president's national security team have been in touch with Egyptian officials and our regional partners to convey the importance of a quick and responsible return of full authority to a democratically elected civilian government as soon as possible; a transparent political process that is inclusive of all parties and groups; avoiding any arbitrary arrests of President Morsi and his supporters; and the responsibility of all groups and parties to avoid violence," said Bernadette Meehan, a White House spokeswoman.
The United States has repeatedly threatened to revoke aid to Egypt since the 2011 Arab Spring revolution. That year, Mr. Leahy said he was prepared to halt all aid to the country if President Hosni Mubarak did not step aside and allow a transitional government to take over. In 2012, Secretary of State Hillary Rodham Clinton warned the Egyptian government that the trials of 43 employees of international organizations could lead to the loss of American funds.
Congressional Republicans this week have expressed less of an appetite for threatening to revoke aid.
"In determining the future of U.S. assistance, the administration should look at the regional picture with our vital national security interests in mind," Senator Bob Corker of Tennesee, the ranking Republican on the Foreign Relations Committee, said Wednesday. "Our long-standing cooperation with Egypt, which is essential for stability in the region, should remain a priority."
Mr. Corker added that he believed that "Congress would stand ready to work with the administration to address any restrictions that stand in the way."
During the Arab Spring uprising in Egypt, Mr. Obama remained noncommittal about his desired outcome until it became clear that Mr. Mubarak's administration had become unsustainable. After Mr. Mubarak stepped aside on Feb. 11, 2011, Mr. Obama threw his support behind the Egyptian people, vowing to back them through a democratic transition.
"The people of Egypt have spoken," Mr. Obama said at a news conference. "Their voices have been heard, and Egypt will never be the same."
"We stand ready to provide whatever assistance is necessary -- and asked for -- to pursue a credible transition to a democracy," he added.
That democratic transition included a presidential election in June 2012, with Mr. Morsi taking 51.7 percent of the vote in a runoff. Although Mr. Morsi quickly took steps to consolidate his own power, ultimately prompting the widespread street demonstrations that began on Saturday, the Obama administration again appears wary of letting revolutionary sentiment drive changes in power. Rather than endorsing the military's decision to remove Mr. Morsi, Mr. Obama on Wednesday claimed allegiance to the "democratic process."
Erin Banco and Thom Shanker contributed reporting.
This article originally appeared in The New York Times.