Actually, MSNBC outlines why its not that simple:

Democrats must clear three hurdles in order to get to a final version of the health-care bill that most legislators in their party can live with.

First, the House must pass the Senate's version of the health-care bill and send it to the president for his signature. It would immediately become law.

But because most House Democrats don't like the Senate bill -- due to the toxic "Cornhusker Kickback," etc. -- a second step is required. The House would then use a budget procedure called reconciliation to passes a much smaller bill of "fixes."

And finally as the third step: the Senate must pass the same fixes as the House. This is the point at which Senate Republicans believe they can trip up the bill's progress.

This three-step process requires House Democrats to trust the Senate counterparts to pass the exact fixes they want -- and some, says Gregg, are understandably skeptical.

"What the president is asking House Democrats to do is hold hands, jump off a cliff, and hope Harry Reid catches them," said GOP Sen. Lamar Alexander. "And Harry Reid is not going to have much incentive to catch the Democrats because the president will have already signed the bill."

Dropping the 'Byrd" on Democrats
In the Senate, reconciliation is a filibuster-proof budget procedure, needing only a simple 51 vote majority. But the Senate's rules for the process require that every provision must be directly linked to a budgetary impact. Any part of the bill that doesn't impact taxes, spending, or government money risks being eliminated by the non-partisan Senate parliamentarian.

The most-used tool to extract questionable provisions is called the Byrd Rule, named after its author, Sen. Robert Byrd (D-WV). 

Republicans are prepared to pick the bill apart to make sure that the Byrd rule is followed to the letter. And the result, Gregg said, could be that some of those "fixes" demanded by Democrats in the House just don't pass muster. "I presume that some of the stuff that gets dropped under Byrd are going to be things which were important to people on the House side and influenced their decision to vote for the bigger bill," he said.

Endless votes on amendments
The rules of reconciliation would also allow Republicans -- and Democrats -- to offer an unlimited number of amendments to change the bill.

Members of either party can offer any changes as long as they fall within the jurisdiction of the Senate Finance and Health committees. So, Republicans say, any amendments that deal with taxes, Medicare, Medicaid, education, pension, or labor issues are fair game.

Republicans also are quick to point out that, if the Senate changes even one word of the bill, it would have to go back to the House to be passed again, causing further delays.

Opponents of the legislation don't deny that delaying final passage of the bill is a part of their strategy.

"There's never a problem with giving the American people an opportunity to express themselves on a piece of legislation they care lot about," Sen. Jon Kyl, (R-AZ), said this week. "And the more opportunity they have to do that from our perspective the better."