Congress has one week left to pass a budget bill to avoid triggering a government shutdown. And given the procedural hurdles such a bill must clear to become law — not to mention the Tea Party's reluctance to throw in the towel on the ObamaCare fight — there may not be enough time left on the calendar to do so.

As a quick refresher: The House last week passed a budget bill — called a continuing resolution — that would fund the government but not ObamaCare. The bill has no chance in the Democratic-led Senate, setting up a showdown between the two chambers that could drag on past the Sept. 30 deadline.

Majority Leader Harry Reid (D-Nev.) on Monday filed a cloture motion on the House bill, which would allow it to move forward to debate. However, under the Senate's arcane rules, the motion can be neither debated nor voted on for two days, meaning the Senate will have to take it up on Wednesday.

That's where Sen. Ted Cruz (R-Texas), the Senate GOP's most vocal opponent of ObamaCare, could play a major role in determining whether a government shutdown occurs.

Democrats need only a simple majority to nix the ObamaCare-defunding language from the bill. And they need only a simple majority to pass a stripped-down resolution, too.

However, as The Washington Post's Ezra Klein notes, there is a 30-hour window for debate following the cloture motion. Cruz and company could burn all that time, pushing the actual vote on cloture to Thursday.

Cruz has also said he will filibuster the cloture vote, though it seems unlikely he will have enough GOPers behind him to pull it off. Sen. Minority Leader Mitch McConnell (R-Ky.) said Monday he would not support a filibuster, as did Sen. John Cornyn (R-Texas), the No. 2 Republican in the upper chamber. Democrats need only six Republican defections to defeat a potential filibuster.

Assuming debate stretches to Thursday and the filibuster fizzles, a successful cloture vote would mean the Senate could, finally, begin to debate the resolution itself after two more days of waiting. Yet even then, there is another 30-hour window for debate in which Cruz could again hold up the process.

If Cruz were to drag debate out as long as possible at each stage, a vote could be pushed back to as late as Sunday, a Democratic aide told The Wall Street Journal. At that point, Congress would have just two days left to strike a deal.

Should the Senate as expected pass a CR sans the defunding provision, the House could quickly sign off on the bill and send it right along to President Obama. However, House Republicans could balk at the Senate's version and instead pass some other untenable bill or bills. For example, under one proposal — suggested by, you guessed it, Cruz — the House could pass piecemeal spending bills, dragging out the process even further.

Leading lawmakers from both parties say they are confident a shutdown can be averted. Sen. Chuck Schumer (D-N.Y.) said Monday it was "very likely we will avoid a shutdown," adding that he believed Republicans were fed up with Cruz and willing to negotiate.

"It's becoming clearer and clearer that Ted Cruz has climbed out on a limb and it is getting sawed off," he said.

Still, with such a cramped schedule, it's more than possible that Congress won't have enough time to push a bill through both chambers before next Tuesday. Then again, at least Congress has some recent experience with avoiding a shutdown at the 11th hour, which was what happened two short years ago.