When President Harry Truman ended segregation in the armed services, critics argued that having blacks and whites serve side by side would disrupt the military.

Six decades later, naysayers on Capitol Hill have tried to use a similar argument to delay lifting a ban on allowing openly gay men and women to serve in the military. But so far, they have failed. Congress took two important votes Thursday that may finally lead to repeal of the 1993 "don't ask, don't tell" law. Unfortunately, though, caveats added to the legislation may aid opponents' stalling tactics.

U.S. Rep. Patrick Murphy (D., Pa.,) an Iraq veteran and chief sponsor of the measure, has led the fight to lift the 17-year-old ban. The House and a Senate committee approved his bill. But it faces an uphill battle in the full Senate, where Republicans may filibuster it, even at the risk of the $760 billion defense spending bill that includes the measure.

During his campaign, President Obama promised gay-rights advocates he would reopen the debate about gays in the military. Now, he needs to show the fortitude necessary to settle the matter.

In a compromise with the Pentagon, the gay-rights measure was amended so that it won't take effect until the Pentagon completes a study of how the policy change will affect the military. That report is due in December.

It's difficult to understand what another study can say about a subject that has been debated for years. But if one more report is what it will take to end the current discrimination against gays and lesbians, then go for it.

The repeal can be implemented 60 days after Obama, the Joint Chiefs of Staff, and the secretary of defense certify it "will not hurt military readiness or unit cohesion."

The current policy certainly has had a negative impact, with 13,500 service personnel dismissed from the armed forces under the rule. They include high-ranking officers as well as Arabic translators and interpreters - the very experts vitally needed in the fight against terrorism.

Of course, there is apprehension among the troops about ending "don't ask, don't tell," but many have said they will serve alongside anyone - regardless of sexual orientation. A recent Gallup poll found 70 percent of Americans support lifting the ban.

It's time for change. Gays who want to help protect their country should be given the opportunity.