Page 2 of 2 --

‘‘Will the plan be affordable? We all want to give children a solid foundation for a bright future, but that also means we can’t saddle them with even more debt,’’ Klein said.

Republican lawmakers also were eager to press Obama for specifics lacking in his speech. For instance, leaders on the Hill were curious if this new expansion would be part of existing programs such as Head Start in the Health and Human Services Department, or if it would start a new program inside the Education Department. They also wanted to know if the new effort would funnel money to states or local governments, or if Washington would administer the program as part of a national pre-K program that is unrivaled in size.

Obama has said he wants to partner with states, but the mechanics of such a joint project were far from clear. White House officials did say the new pre-kindergarten plans would be set up by states and independent of Washington’s meddling with the details.

Speaking broadly about its virtues, Obama said such an initiative would shrink the achievement gap for poor and minority students and strengthen a competitive workforce that would attract companies to create jobs in the U.S.

‘‘This works. We know it works,’’ Obama said. ‘‘If you are looking for a good bang for your educational buck, this is it right here.’’

Republicans and conservatives have questioned the effectiveness of Head Start programs, citing studies such as a Health and Human Services Department report last year showing that, while at-risk students enrolled in the pre-kindergarten programs saw tremendous gains in vocabulary and social development, those benefits largely faded by the time students reached third grade.

Scores of other studies, however, were more favorable toward the program, which has been shown to make at-risk students more likely to complete high school and avoid criminal arrests. In pure dollars and cents, academics called it a smart investment.

Even in states like Georgia, showcased by Obama in his remarks Thursday, the results have been mixed. Georgia made a commitment to universal pre-K in 1995 and it’s been a slow climb, with about 60 percent of eligible children currently enrolled. And Georgia’s high school graduation rate is among the lowest in the nation.

___

Elliott reported from Washington. Associated Press writer Jim Kuhnhenn and AP White House Correspondent Julie Pace contributed to this report.