U.S. House of Representatives began their final debate Sunday afternoon before a crucial vote on the health insurance reform later in the day.

The House began procedural debate shortly after one o'clock in the afternoon. They are scheduled to begin voting after two. The vote could last as long as the whole afternoon, and well into the night.

Earlier in the day, House Democratic Leader Steny Hoyer said Democrats have garnered enough votes to push the healthcare legislation through the lower chamber.

The showdown consists of three votes, the first one on rules structuring debate, which is expected to happen shortly after two. The vote could be an indication on how much support the Democrats now have.

After the first vote, House members are to embark on further debate, and then they will take up the bills themselves. They will first vote on a Senate version of the health reform, which passed the upper chamber last December. If passed by the House, it will go straight to President Barack Obama for his signature.

The last vote, which is expected to happen sometime around seven or eight at night, will be on a fix-it bill of the Senate bill, which many House members find unable to reconcile themselves with just as it is. If passed, it will head to the Senate.

The fix-it bill is part of the legislative procedure called reconciliation. According to reconciliation rules, the Senate needs only 51 votes to pass it. Democrats employ this method to prevent a Republican filibuster, as they have lost their supermajority of 60 votes earlier this year in the upper chamber.

Senate Majority Leader Harry Reid has informed Hoyer that they have enough votes to pass the fix-it bill in the Senate. But Republicans have vowed to swarm it with "hundreds of amendments."