Just days after a Pentagon study concluded gays could serve openly in the US military without harming its ability to fight, the services' top uniformed officers are planning to tell a Senate panel they are not so sure.
The US Marines commandant and chiefs for three other service branches have been widely expected to say that they remained reluctant to lift the ban on openly gay service because the troops who expressed the gravest concerns are the ones fighting on the front lines of combat.
The congressional testimony by the four branch leaders - Marine Commandant General James Amos, Army Chief of Staff General George Casey, Air Force Chief of Staff General Norton Schwartz and Chief of Naval Operations Admiral Gary Roughead - will be the first since Tuesday's release of the Pentagon study on the "don't ask, don't tell" ban on gays in military.
The study found that most troops surveyed felt the ban could be repealed without causing serious problems.
At the same time, almost 60% of those in the Marine Corps and in Army combat units, such as infantry and special operations, said they thought allowing gays to be open about their sexual orientation would hurt their units' ability to fight on the battlefield.
"There's risk involved; I'm trying to determine how to measure that risk," Com Gen Amos said last month in San Diego, California.
"This is not a social thing. This is combat effectiveness. That's what the country pays its Marines to do."
Marine General James Cartwright, the number two officer on the Joint Chiefs of Staff, also was expected to testify on Friday. But he probably will support the repeal.
Gen Cartwright and other Pentagon leaders have said they prefer Congress to a court order if there is to be a change in policy.
Earlier this autumn, a federal judge in California shook the Pentagon by ruling the ban unconstitutional and ordering the military to cease enforcement.