Two longtime lawmakers — Republican Sen. Thad Cochran of Mississippi and Democratic Rep. Charles Rangel of New York — barely clung to nominations to their seats Tuesday.
But those rare exciting races that draw national attention are misleading. Most of the House candidates, about 60 percent so far, didn't have a soul running against them. Only a few faced a challenger who posed a real threat. No senator has been defeated yet.
What about November, when Republicans and Democrats face off in the general election?
It looks to be a dramatic midterm, all right, with Republicans pushing to seize control of the Senate. More incumbents will be vulnerable in the general election than the primaries. Still, the vast majority of sitting lawmakers are snug in their seats.
Over the past five decades, voters have routinely returned 9 of 10 incumbent candidates to the House. Senate races are a bit less predictable, but usually more than 80 percent of incumbents win.
Consider 2010, which was a "bad year" for incumbents. A wave of angry voters swept Republicans into the House majority. Fifty-eight House members were ousted that year, nearly all of them Democrats. President Barack Obama called it a "shellacking."
Yet even in that remarkable midterm, voters rehired 85 percent of Congress members who were on the ballot.
This year, Congress logged a confidence rating of 7 percent, the lowest Gallup has measured for any institution, ever. People don't put much attachment to their own representative anymore, either. An Associated Press-GfK poll last month found that 65 percent of Americans say their own House member should lose.
So why do these people keep winning?
It's harder for challengers to sell themselves to voters. Incumbents wield tremendous advantages. They raise big bucks from special interests, use their congressional offices to send voters mass mailings, build ties to businesses and advocacy groups in their districts, and benefit from name recognition. They have staff members back home working to keep constituents happy.