WASHINGTON — The Republican-led House backed a measure Thursday that seeks to bar women from being required to register for a potential military draft, a victory for social conservatives who fear that forcing females to sign up is another step toward the blurring of gender lines.

By a vote of 217 to 203, lawmakers approved an amendment that would block the Selective Service System from using any money to alter draft registration requirements that currently apply only to men between the ages of 18 and 25.

The amendment, sponsored by Rep. Warren Davidson, R-Ohio, was added to a financial services spending bill. The House also approved an amendment by Rep. Paul Gosar, R-Ariz., that would block any money in the bill from being used for sanctuary cities, a term for jurisdictions that resist turning over immigrants to federal authorities.

Davidson said much more study is necessary before such a significant, if largely symbolic, change to the draft is made. The U.S. has not had a military draft since 1973, in the waning years of the Vietnam War era, and the odds for another wide-scale draft are remote. Still, the draft registration requirement remains for men, and many lawmakers believe women should be included.

The House vote comes just a few weeks after the Senate passed an annual defense policy bill that mandates for the first time in history that young women sign up for a draft. That measure calls for women to sign up with the Selective Service within 30 days of turning 18, beginning in January 2018.

The push in the Senate to lift the exclusion was triggered by the Pentagon's decision late last year to open all front-line combat jobs to women. After gender restrictions to military service were erased, the top uniformed officers in each of the military branches expressed support during congressional testimony for requiring women to register. At the same time, they said the all-volunteer force is working and they didn't want a return to conscription.

Davidson said delaying the requirement gives lawmakers time "to talk with our families, talk with young women, and then take a more considered action."

The House didn't include a similar provision in its version of the annual defense policy bill. Instead there's a measure to study whether the Selective Service is even needed at a time when the armed forces get plenty of qualified volunteers, making the possibility of a draft remote.

The House on Wednesday rejected an amendment to put the Selective Service System out of business by denying the agency's $23 million annual budget.

Rep. Peter DeFazio, D-Ore., who drafted the amendment, said the Selective Service is obsolete and archaic.

But other lawmakers pushed back. Rep. Ander Crenshaw, R-Fla., said the $23 million is a "small price to pay for an agency that has the potential to avert a crisis should the draft ever need to be reinstated."

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