The Eye

Most of Cao's expenses during the third quarter -- $250,000 -- came from the high cost, high reward process of direct mail fundraising.

After raising less than $150,000 during the first three months of the year and reporting an unimpressive $61,000 in the bank on March 31, Cao reported $370,000 in receipts in the second quarter and almost $340,000 in cash on hand as of June 30.

And while his first-quarter report included donations from just a handful of fellow Republican lawmakers, Cao's second-quarter report was boosted by checks from more than 15 in of his colleagues, including many Republican leaders. During the third quarter, Cao received checks from GOP Reps. John Mica of Florida, Shelley Moore Capito of West Virginia, John Kline of Minnesota, Glenn Thompson of Pennsylvania and Lynn Westmoreland of Georgia.

Democrat Cedric Richmond, a state representative, filed in mid-August to run against Cao and said earlier this month that he will report raising more than $100,000 in the third quarter.

Another state representative, Democrat Juan LaFonta, has also filed for the race.

CQ Politics views Cao as the most vulnerable Republican in the House in 2010 and rates the general election race "Likely Democratic."

To follow the 2010 House races, check out the CQ Politics election map