The GOP approval rating has been going down in the CNN poll since their 2010 victories: in the October 27-30 version, the Republican Party had a small plurality in approval, at 44 - 43. But since last fall's election they've seen a steady downward trend in the survey, to the current low, which is the highest disapproval rating in the CNN poll in the last twenty years.
The Tea Party itself actually has a lower disapproval rating at 51% than the Republican Party, and only a slightly lower approval rating at 31%.
CNN was also quick to point out possible consequences of such high dissatisfaction with Congress. From the report:
Only 41 percent of people questioned say the lawmaker in their district in the U.S. House of Representatives deserves to be re-elected - the first time ever in CNN polling that that figure has dropped below 50 percent. Forty-nine percent say their representative doesn't deserve to be re-elected in 2012. And with ten percent unsure, it's the first time that a majority has indicated that they would boot their representative out of office if they had the chance today.
The CNN poll used telephone interviews with 1,008 adult Americans, and was conducted from August 5th to the 7th. The sampling error is plus or minus three precent.