By DONNA CASSATA 08/29/13

WASHINGTON -- Wary of another war, congressional Republicans and Democrats pressed President Barack Obama to explain why the U.S. military should attack Syria and involve Americans in the deadly civil conflict that has roiled the Mideast.

"What is the intended effect of the potential military strikes?" House Speaker John Boehner, R-Ohio, wrote the president on Wednesday as the drumbeat of war grew louder.

Exasperated members of the House and Senate said the president has failed to make a case for U.S. military action against Syria despite the administration's conclusion that the Syrian government carried out a large-scale chemical weapons attack against civilians last week. An exception was Democratic Sen. Robert Menendez, chairman of the Senate Foreign Relations Committee, who said Thursday that Obama should take some form of action to send a message to Syrian President Bashar Assad and his regime.

The administration was planning a teleconference briefing Thursday night on Syria for leaders of the House and Senate and national security committees, U.S. officials and congressional aides said.

Obama's national security adviser and intelligence chief, Susan Rice and James Clapper, were scheduled to talk to members of Congress along with Secretary of State John Kerry, Defense Secretary Chuck Hagel and Adm. James Winnefeld, the vice chairman of the Joint Chiefs of Staff, congressional aides said.

The administration signaled Wednesday that it would act against the Syrian government even without the backing of allies or the United Nations in response to the alleged chemical weapons attack outside the Syrian capital of Damascus on Aug. 21.

Some lawmakers insisted that Obama, despite his standing as commander in chief, cannot unilaterally order military action against Syria without congressional authorization.

The president said in a PBS interview Wednesday that he had not made a decision about how the United States would respond.

Menendez, however, said he favors action by Obama and said the president has several options, including missile attacks against critical elements or strikes on regime troops in Damascus.

"It's beyond Assad and Syria," Menendez said on CBS "This Morning." `'It's really a question of whether or not you send an international message that weapons like chemical weapons cannot be used against innocent civilians."

Menendez, D-N.J., said he would like to see Obama come before Congress but that Obama does have authority to act without congressional approval: "... the president has, under the War Powers Act, the ability to go ahead if he believes the national security of the United States is at stake," Menendez said.

But another Democrat on the Foreign Relations panel, Connecticut Sen. Chris Murphy, has questioned whether there is an imminent threat to U.S. interests and warned against military strikes that could draw the United States into a long-term war that could cause even more Syrian deaths.

Menendez said Obama has a number of options, but the actions are "not about regime change."

"Nor is it about a long-term engagement, nor is it about boots on ground," Menendez said.

In his letter, Boehner underscored that he has been supportive of administration policy to date as Obama has called for Assad to resign and insisted that the use of deadly chemical weapons would be a gross violation of international norms.

Boehner wrote that in light of the administration's contention that the Syrian government had used chemical weapons against its people, Obama should provide "a clear, unambiguous explanation of how military action – which is a means, not a policy – will secure U.S. objectives."

Boehner asked Obama to "personally make the case to the American people and Congress for how potential military action will secure American national security interests, preserve American credibility, deter the future use of chemical weapons, and, critically, be a part of our broader policy and strategy."

The speaker also pressed the president to provide a legal justification for any U.S. military action.

There was no immediate reaction from the White House to Boehner's request.

In the House, 98 Republicans and 18 Democrats have signed a letter to Obama demanding that he seek congressional authorization for any military action against Syria. The letter written by Rep. Scott Rigell, R-Va., argues that intervention without a direct threat to the United States and without Congress' approval would be unconstitutional.

Washington Rep. Adam Smith, the senior Democrat on the House Armed Services Committee, cautioned that an attack might be ineffective and might draw the United States into the Syrian civil war, now in its third year.

"Simply lashing out with military force under the banner of `doing something' will not secure our interests in Syria," Smith said in a statement.

Oklahoma Sen. Jim Inhofe, the senior Republican on the Senate Armed Services Committee, said he informed the administration that he could not support any military strike against Syria unless Obama presents a detailed strategy to Congress and provides a defense budget to support any action.

An increasing number of lawmakers have asked what would be the end result of U.S. military intervention against a Mideast country where the Assad government and rebel forces have struggled for more than two years, with an estimated 100,000 killed and millions displaced.

"The war in Syria has no clear national security connection to the United States, and victory by either side will not necessarily bring into power people friendly to the United States," Sen. Rand Paul, R-Ky., said.

In his letter, Boehner raised 14 questions that he asked Obama to answer, including what the administration would do if Syria retaliates against U.S. allies in the region, whether the administration would launch additional military strikes if the initial ones proved ineffective and how any operation will be paid for