Lawmakers in Washington locked in a stalemate over how to raise the nations $14.29 trillion debt limit may have a bit more time to avoid an unprecedented default than previously believed.

Thanks to a surprisingly strong influx of tax revenue during the second half of July, the U.S. may not actually run out of cash until August 10 -- eight days after the infamous August 2 deadline the Treasury Department laid out, a new research note from Barclays (BCS) contends.

After studying tax receipts since July 14, the Barclays analysts believe the U.S. will now be able to meet $32 billion in payments due on August 3, the bulk of which is a $22 billion Social Security payment that President Barack Obama famously warned was in doubt.

Thats because tax inflows over the five-day period from July 14 have been $14 billion higher than previously assumed, allowing the Treasury Department to easily overcome a $2 billion shortfall it was facing on August 3. At the same time, Barclays estimates actual expenditures have been $1 billion lower than its earlier assumptions.

If Barclays analysts are correct, the later drop-dead date could give lawmakers and the White House much needed time to reach an agreement to raise the debt limit and slash spending. It could also give the ratings companies like Moody's and Standard & Poor's a reason to hold off on downgrading the nations coveted AAA credit rating, an outcome seen as more likely than a default but that would have negative consequences like higher borrowing costs.

However, a Treasury Department spokesperson reaffirmed on Monday the August 2 deadline to FOX Business and declined to comment on the Barclays report or a similar one from UBS (UBS). 

Barclays itself warned in its research note it is not positive about its August 10 estimated deadline and said its possible it is unaware of a big payment the U.S. was budgeting for that didnt appear in the 2010 period.

It is extremely difficult to be sure about future cash inflows and outlays, the analysts wrote. If inflows are coming in considerably stronger than we expect, the extra $14 billion (all other assumptions remaining the same) seems set to take us past August 2. It is always possible, however, that just as inflows have surprised to the upside in the past five days, they will surprise to the downside over the next few.

With that in mind, Barclays believes the Treasury Department should start prioritizing its payments a few days before the August 10 date to ensure making a big coupon payment that is due on August 15.

Talks in Washington collapsed once again over the weekend as Republicans and Democrats struggle to agree on whether or not to raise taxes and how much money should be cut. 

Worries about politicians ability to avoid a default or a downgrade helped send the Dow Jones Industrial Average dropping more than 100 points Monday morning before it recovered.

The sooner policymakers come to a deal, the sooner this source of uncertainty will disappear, Barclays wrote.

Follow Matt Egan on Twitter @MattMEgan5