President Barack Obama must participate directly in negotiations next month to merge the House and Senate's differing versions of healthcare reform on "a day to day, hour by hour" basis, Rep. Elijah Cummings (D-Md.) stressed Monday.

Lawmakers in both chambers will have to reconcile a number of differences in their healthcare legislation once the Senate passes its bill, but the process of resolving those debates would be daunting without the White House's input, the congressman added.

"I have absolutely no doubt that there will be some changes, and we're going to have to call on the president to get very much involved in this and to get this through," Cummings said.

Fierce debate in the Senate over healthcare reform has put House Democrats in a somewhat precarious position.

A number of key swing votes in the upper chamber have made explicitly clear they will not vote for a conference report containing many of the proposals House lawmakers strongly support.

At the same time, a smattering of House lawmakers are also likely to reject many of the Senate's big changes -- from its new taxes to its exclusion of a public option, two elements Cummings said he wanted retained in the final bill.

While the congressman did not specify his vote for the conference report was contingent on those changes, he ultimately stressed "we're going to have to push real hard on our side" during the conference process.

"Again, I don't expect to like every aspect [of the bill] when it comes out," Cummings acknowledged. "But the fact remains that we're going to insure 31 million more people, and that makes me happy."