Democratic leaders have identified the “broad outlines” of a new bill aimed at stimulating the U.S. economy, but the proposal won’t begin moving at least until July, Sen. Charles E. Schumer , D-N.Y., said Wednesday.

Democrats have been contemplating a second effort to inject money this year into the faltering economy. The idea appears to have gained traction, particularly among congressional leaders, since Monday when presumptive Democratic presidential nominee Sen. Barack Obama of Illinois outlined a $50 billion stimulus proposal that will serve as the centerpiece of a two-week economic tour of battleground states.

Though the prospects for a second stimulus package are slim, the debate gives congressional Democrats an opportunity to rally around Obama.

The massive economic stimulus package enacted in February focused on tax breaks for businesses and rebates for individuals and families.

Obama has proposed a second round of rebate checks, an extension of unemployment insurance, aid to state governments and a new $10 billion fund to help stem the tide of home foreclosures.

He also proposed increasing investment in infrastructure such as roads, schools and bridges.

“There’s a need for additional targeted stimulus,” said Senate Budget Chairman Kent Conrad , D-N.D.

Schumer said infrastructure investment and a second round of rebate checks could be part of the new package, which Democrats are likely to unveil after the July Fourth recess.

Conrad said an unemployment insurance extension also should be part of the package if it is not enacted before then.

Republicans have been wary of any new stimulus package before assessing the results of the first.

Schumer said action would be delayed until July, in part to allow time to gauge the impact of that package.