Alan Mollohan (D), who has represented West Virginia’s 1st District since 1983, was defeated in Tuesday’s Democratic primary by Mike Oliverio, a state legislator since 1993. This is big news for a number of reasons. First, long-time incumbents rarely get beaten in primaries. Incumbency advantages—stemming from a number of sources– are great for general elections, but greater still in the primaries.

The second reason this is big news is the sea change in ideology this election implies. Oliverio is conservative. No, really, really super duper conservative. According to Wikipedia, he’s pro-life, and supports a state constitutional ban on gay marriage. He serves as one of the WV chairs of the libertarian/conservative American Legislative Exchange Council, which aims to “to advance the Jeffersonian principles of free markets, limited government, federalism, and individual liberty”, and which features a button on how to “crack ACORN in your state” on its home page. And George W. Bush explicitly name-checked Oliverio for his support of the Sam Alito nomination to the US Supreme court.

Exactly how conservative is he? Our common space score for him is 0.25, which puts him into the 96th percentile of his party for conservatism in his state for the last decade or so. He’s about as conservative as the average WV state Republican, and more conservative than many of them.

If he wins the general election in November, he’d be replacing Mollohan, who scores a pretty liberal –0.5 (remember that these scores put Congress and state legislatures onto a common scale for comparisons). That’s average for WV Democrats over the past 15 years or so.

For comparison, if Oliverio were to remain ideologically consistent (something I consider very likely for all “graduating” state legislators), he’d be more conservative than the sole Republican in the state delegation to Congress, Shelley Capito. He’d be more conservative than a bunch of other Republicans, too. He’d be far more conservative than the most conservative Democrat in Congress, Idaho’s Walt Minnick, who voted against health care reform, the stimulus, and the Waxman-Markey environment bill.

That’d be amazing. Remember, in our polarized times, no Republican in Congress is to the left of any Democrat (and, vice versa, no Democrat is to the right of any Republican). If elected to Congress, Oliverio could be the first conservative Democrat in a long time to make at least some Republicans look liberal.