The Congress faces an August 2 deadline for raising the government's $14.3 trillion limit on borrowing and averting a potentially catastrophic default.

President Barack Obama and congressional leaders -- Republicans and Democrats -- have been unable to work out a deal after months of negotiating. In a last-ditch move, each party is going ahead with separate legislation that might not be finalized until the very last minute, if then.

Here is a timeline, according to aides, on how the respective bills could work their way through Congress.

MONDAY

Senate Majority Leader Harry Reid unveiled details of the Democratic plan to cut $2.7 trillion in spending over 10 years and raise the nation's debt limit by the same amount. That would give the U.S. Treasury enough borrowing authority to extend through 2012. Democrats hope to win some Republican support by not including any tax increases.

Meanwhile, House of Representatives Speaker John Boehner is readying the competing a Republican plan: A $900 billion debt limit increase coupled with around $1 trillion in spending cuts. A second vote early next year to raise the debt limit again would be required and theoretically would be coupled with savings from reforming taxes and huge benefit programs for the elderly and poor.

WEDNESDAY

The Republican-controlled House, possibly late in the day, could try to pass the Boehner plan. Leaders would have to work hard to find enough votes from each party for passage.

Alternately, the House could wait a little longer to pass a bill and send it to the Senate, thus increasing the pressure on the Senate to accept its approach. But the Senate's No. 2 Democrat, Senator Richard Durbin, says it will be clear by week's end that the Boehner plan cannot pass the Senate.

THURSDAY

The Democratic-controlled Senate could vote to limit debate on the Reid plan and then spend most of the rest of the week debating the legislation.

SUNDAY

Time potentially expires for debating the Democratic plan and the Senate could vote to pass it.

FINAL DAYS THROUGH AUG. 2

Obama and congressional leaders work out a way to blend the bills passed by the House and Senate. Each chamber would then have to pass the final version and hurriedly send it to Obama to sign into law.

FAILURE?

If Congress fails to pass the necessary legislation, Obama would have to decide whether to use executive powers to continue Treasury Department borrowing and face legal challenges.

(Reporting by Richard Cowan, editing by Todd Eastham)