Their letter was prompted by the refusal of Army Spc. Michael New to wear the blue U.N. insignia. Specialist New, whose unit is to be deployed soon on a U.N. mission to Macedonia in former Yugoslavia, is facing punishment for his act.
In their letter, the conservatives, led by Republican Rep. David Funderburk of North Carolina, said they were "deeply concerned" about "important constitutional issues" raised by Specialist New's refusal.
The administration's position is that the president, as commander in chief, has authority to deploy U.S troops to defend the national interest, and that such authority can include preserving international peace and security.
U.S. troops, it asserts, do not transfer their allegiance to the United Nations, and, though they might be under the "tactical control" of foreign officers, they remain under a direct chain of U.S. military command.
But the critics in Congress, demanding a legal analysis of the deployment orders for Specialist New and his unit, said: "The Congress has not been consulted on most of these acts, despite the fact that we have certain clear-cut constitutional duties regarding these matters."
Their letter was the latest sign of resistance on Capitol Hill to deploying U.S. troops on U.N. missions. Critics, mainly conservative Republicans, see U.N. command as impinging on U.S. authority over American troops and as often being driven by political rather than military priorities.
The House already has voted to bar U.N. command of U.S. forces, and the Senate has passed similar legislation. The differences between the two approaches must still be resolved.
Sen. Strom Thurmond, chairman of the Armed Service Committee, will open hearings next week into the administration's commitment of up to 25,000 U.S. troops to a U.N. peace-enforcement force in Bosnia.
Mr. Thurmond said: "I do not believe that Congress and the American people are prepared to support U.S. involvement in Bosnia without clarifying the numerous issues involved in such a commitment."
The administration's position is that stability in Europe and U.S. leadership of NATO are at stake and that they justify the deployment of a U.S. contingent in an international force, expected to total around 60,000, once a peace agreement is signed in Bosnia.
Specialist New, a medic with an exemplary record, paraded Tuesday in ordinary battle dress while his comrades wore blue U.N. patches and baseball caps. He was accused of disobeying a lawful order.
After Specialist New's refusal to wear U.N. gear, his battalion commander, Lt. Col. Stephen Layfield, offered the 22-year-old soldier the option of a court-martial or nonjudicial punishment, which would involve lesser discipline.