President Barack Obama fulfilled a campaign promise Wednesday and signed a landmark law repealing the ban on gay men and women serving openly in the armed services.

The signing ceremony was a breakthrough moment for gays in the United States, for the military and for Mr. Obama himself. The president vowed during his 2008 campaign to repeal the law and had faced pressure from liberals, a significant base within his Democratic party, a significant base in his Democratic party, who complained he was not acting swiftly enough.

The new law is the second of three victories in what has turned out for Mr. Obama to be a surprisingly productive postelection Congress. Weeks after his self—described “shellacking” in the Nov. 2 congressional elections, he has won lopsided approval of a tax cut compromise with the opposition Republicans, and the Democratic—controlled Senate delivered Wednesday by passing Obama’s top foreign policy goal, ratification of a new nuclear arms reduction treaty with Russia.

The new law affecting the military ends the 17—year—old “don’t ask, don’t tell” policy that forced gays to hide their sexual orientation or face dismissal. Its repeal comes as American public opinion on such issues as gay marriage and gay rights in general has grown more tolerant.

“I say to all Americans, gay or straight, who want nothing more than to defend this country in uniform, your country needs you, your country wants you, and we will be honoured to welcome you into the ranks of the finest military the world has ever known,” Obama said.

Pentagon officials must first complete implementation plans before lifting the old policy, and they must certify to lawmakers that it will not damage combat readiness, as critics charge. Opponents of the repeal also had said it would harm unit cohesion; could prompt some to leave the services or not to sign up in the first place, and would be a distraction at a time when the armed forces are fighting two wars. The Pentagon is treating those issues carefully as it develops an implementation plan for allowing openly gay members to join the fighting forces.

“We are not going to be dragging our feet to get this done,” Mr. Obama said.

Mr. Obama’s participation in two of the events, signing the tax bill and ending the ban on gays in the military, could not have been more different in tone.

The tax deal divided Democrats and forced Mr. Obama to accept extensions of tax cuts for the wealthiest, a step he had promised not to take. With Senate Republican leader Mitch McConnell at his side during that bill signing, Mr. Obama seemed dutiful and subdued.

Wednesday’s signing of the repeal of “don’t ask, don’t tell” had the feel of a political rally. Speaking in the Interior Department’s auditorium, Mr. Obama appeared in his element as shouts of “Thank you, Mr. President!” interrupted him.

“I couldn’t be prouder,” Mr. Obama said.

Mr. Obama hailed the “courage and vision” of Defence Secretary Robert Gates and praised Gates and Joint Chiefs of Staff Chairman Adm. Mike Mullen, who advocated changing the law.

“No longer will tens of thousands of Americans in uniform be asked to live a lie, or look over their shoulder in order to serve the country that they love,” Mr. Obama said.

The Pentagon now must begin addressing the practical consequences of the law. Guidelines must be completed that cover a host of questions, from how to educate troops to how sexual orientation should be handled in making barracks assignments.

While officials have avoided timetables, the process will probably take months.

Born 17 years ago as a compromise between President Bill Clinton and a resistant Pentagon, the “don’t ask, don’t tell” policy became for gay rights campaigners a notorious roadblock on the way to full acceptance.

Military and administration officials are wrestling with numerous legal questions raised by the end of the ban -- knowing that courts are waiting in the wings. They include what to do about pending expulsion proceedings, and when those ousted under the old policy might apply to rejoin the armed forces.

More In: International | News