A couple of weeks ago, the 110th Congress seemed universally poised for a bipartisan smackdown with the President over the unpopular war in Iraq. Controlled by Democrats, the Senate was going to paint a scarlet letter on any troop increase in Iraq... calling it "not in the national interest." It looked like quite a few Republicans might jump aboard, too. Ouch.

What's happened since is fascinating. But before we get to that, you need to understand a little bit about the quirks of the Senate. I'll try to make it as painless as possible.

Democrats hold a Senate majority of 51 seats; Republicans have 49. But 51 votes isn't enough to pass an Iraq Resolution or anything else because of a little tactical maneuver called a "filibuster." It takes just one Senator to put the skids on things with a filibuster; it takes a full 60 votes to stop him. To reach 60 in a Senate that's almost evenly split, each side needs the vote of every Senator in their own party, plus nine to 11 members of the other party. That's a tall order.

Okay, I tried to make it painless. Now here's how all that comes into play.

The original harshest Iraq Resolution (Biden-D, Levin-D) is toast. It couldn't get near the 60 votes needed because too many Senators were worried it would be viewed as empowering the enemy and being unsupportive of the troops. In its place are a whole bunch of Iraq resolution wannabes. The two big ones at issue couldn't be more opposite. We're not talking yen and yang opposites that somehow fit together nicely in the end. It's more like the difference between lions and butterflies.

Call Senator John Warner's (R-VA) resolution (co-sponsored by Democrat Carl Levin) the lion. It opposes the President's troop increase, but to try to get more support it also includes a pledge not to cut funds for troops in the field. On the other hand, the butterfly is brought to you by those old dealmakers Republican Senators John McCain and Lindsey Graham. Their resolution supports the President's plan. And despite all the anti-Bush rhetoric you've been hearing, the Senate is actually about evenly split between the pro-Bush and anti-Bush resolutions. Neither has the magic 60 votes.

Follow me, if you dare, one step further. There's a third resolution that appears to have more support than any of the others. It's from Republican Judd Gregg. It simply pledges not to cut funding for the War. It's something most Republicans and some Democrats can get on board with. But it's also what's led to last night's blocking of the whole Iraq resolution debate. The two sides are in a stalemate over what the rules would be in voting on the Gregg resolution. Each side wants rules that would allow them to spin the outcome to their own advantage.

This is where it becomes so fascinating. Here we sit stalled with Congress controlled by Democrats, but the three most likely Iraq resolutions being led by Republicans. Not only that, but two of them would probably make President Bush pretty darn happy. Not exactly what Democrats had in mind when they won a majority in Congress and promised they'd do something to bring the whole Iraq nightmare to a close.

To be continued.

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    Sharyl Attkisson is a CBS News investigative correspondent based in Washington.