Washington (CNN) - One of first lady Michelle Obama's top priorities - promoting child nutrition and combating obesity - is running into a major roadblock in the House of Representatives.
But, in an unusual twist, the opposition is not coming from Republicans. It's coming from liberal Democrats.
A key bloc of House Democrats is threatening to vote against a Senate-passed child nutrition bill because it pays for the new initiatives in part by taking $2.2 billion slated for food stamps.
Rep. Jim McGovern, D-Massachusetts, predicted the Democratic votes aren't there to pass the bill before the House leaves later this week, unless the White House gives strong assurances to House Democrats it will replenish the money for the food stamp program.
"We're not going to tolerate robbing the poor to pay for every piece of legislation," McGovern told CNN Tuesday.
If the House doesn't pass the measure before September 30 - the end of the fiscal year - existing nutrition programs will get a short-term funding extension in another bill that Congress is expected to pass this week before members leave to campaign. But the new programs pushed by the first lady will have to wait until after the election, when the House is likely to take up the bill in a lame duck session.
An aide to the first lady tells CNN that Mrs. Obama has been personally making phone calls to Speaker Nancy Pelosi and other House leaders, and her staff has pressed the issue in regular meetings on the issue.
The aide would not say exactly how many calls the first lady has made.
The first lady publicly called on the House to pass the Senate bill in a recent speech in New Orleans, and also pressed the Congressional Black Caucus and Congressional Hispanic Caucus in separate remarks to both groups this month.
While praising the first lady's focus on the issue, McGovern slammed Senate Democrats for using money from the Supplemental Nutrition Assistance program (SNAP) to pay for the $4.5 billion nutrition bill. House liberals support the programs in the Senate bill, but many of them feel burned after reluctantly voting this summer to take significant money from the food stamp program to pay for legislation that sent money to cash-strapped states to avoid teacher layoffs.
"The SNAP program shouldn't be an ATM," McGovern said. He and another 105 House Democrats sent a letter to Pelosi last month criticizing the Senate's bill, arguing that "this is one of the more egregious cases of robbing Peter to pay Paul, and is a vote we do not take lightly."
A frustrated McGovern noted that members of his own party in the Senate came up with the mechanism to pay for the bill in an effort to push it forward. "I think there's a calculation over in the Senate that robbing from poor people has no political consequences," he said.
Congress has not updated school lunch programs in five years. The new reauthorization bill includes many items that the first lady has championed as part of her "Let's move" initiative to combat child obesity. Among other things, it provides more money to poor areas to subsidize free meals and requires nutrition programs to include healthier foods.
To help offset the higher cost of including more fruits and vegetables, the bill increases the reimbursement rate for school lunches.
House Majority Leader Steny Hoyer, D-Maryland, included the child nutrition bill on a list of bills the Senate has passed and that the House could vote on this week. But senior House Democratic leadership aides say no decision has been made yet on whether the House will try to act before it leaves for the midterm election later this week.
McGovern insists the fix is easy if the administration pledges to pay back the funds used in the Senate bill. He said leaders are still discussing the matter with the White House, saying that "it's in their court right now."
– CNN Senior Congressional Correspondent Dana Bash contributed to this report