It isn't surprising given the President's low approval rating and disappointing job numbers but Americans are shifting to favor the GOP in overwelming numbers. Read a piece on the subject from todays Wall Street Journal:
Republicans have solidified support among voters who had drifted from the party in recent elections, putting the GOP in position for a strong comeback in November's mid-term campaign, according to a new Wall Street Journal/NBC News poll.
The findings suggest that public opinion has hardened in advance of the 2010 elections, making it tougher for Democrats to translate their legislative successes, or a tentatively improving U.S. economy, into gains among voters.
Republicans have reassembled their coalition by reconnecting with independents, seniors, blue-collar voters, suburban women and small town and rural voters—all of whom had moved away from the party in the 2006 elections, in which Republicans lost control of the House. Those voter groups now favor GOP control of Congress.