Anything other than a Rand Paul romp to victory tonight would be a major upset. Grayson has not led Paul in any public poll (other than one released by his own campaign) since last fall, and the most recent surveys, by PPP and the Republican firm Magellen Strategies, have both shown undecided voters breaking overwhelmingly for Paul. PPP has Paul up 52/34, and Magellen shows him up 55/30. Paul's only area of weakness, according to Magellen, is in the 5th congressional district, the "mountain Republican" area of eastern Kentucky where ideological conservatism, particularly as expressed in Paul's hostility to federal programs benefitting Kentucky, has never been very strong. But Grayson's likely margin in the 5th can't offset landslide Paul wins in much of the rest of the state.
Media interpretations of the Republican Senate primary will be interesting. Given Paul's parentage and quasi-libertarian views, the results will likely be taken as further evidence of an anti-incumbent, "insurgent" mood fed by unhappy independent voters. But a couple of cautionary notes on that meme: Kentucky has a closed primary system with a very early cutoff date for registration changes, so independents are quite literally not going to be a factor in Paul's win or in the Democratic results, for that matter. Furthermore, there's no incumbent in the race, and the actual incumbent, Jim Bunning, has endorsed Paul. And while Grayson's impending loss is indeed humuliating for Mitch McConnell, it's not at all clear the contest is some sort of referendum on his leadership. According to the latest PPP survey, Paul voters want McConnell to remain in his leadership post by a 58/22 margin.
In fact, PPP suggests that what's feeding the Paul surge is a segment of self-conscious Republican voters who want their party to move ideologically to the right. According to PPP's Tom Jensen:
32% of likely primary voters think the party is too liberal and Paul has a 71-21 advantage with them that accounts for almost his entire polling lead. With the other 68% of voters who don't think the party is too liberal Paul is ahead only 45-41.
Paul's status as the candidate of "movement conservative" Republicans rather than tea-party independents or self-conscious libertarians, is buttressed by the endorsements he received from Sarah Palin, Jim DeMint and (in a reversal of an earlier Grayson endorsement) James Dobson.
In any event, you should take some of the hype you will hear tonight about Rand Paul's "insurgency" with a grain of salt.
Meanwhile, the contest to choose a Democratic opponent for Paul is looking to be a very close race. Mongiardo, who nearly defeated Bunning six years ago, has been the better known candidate throughout the race, and has led Conway in most polls, though the undecided vote has also been relatively high. Conway has had a significant but not overwhelming financial edge, and seems to have some momentum; a late SUSA poll has the race dead even, but there remains a significant undecided vote. PPP's final poll at the beginning of May, which showed Mongiardo up 37/26, also showed 27% undecided.
While Conway was recently endorsed by MoveOn, and has attracted general support from netroots progressives, the race has not revolved much around ideology. Conway has said he would have voted for health reform in the Senate, while Mongiardo opposed the bill for "not going far enough." Both candidates oppose cap-and-trade, as you might expect in a coal-producing state. But generally, as the Cook Political Report's Jennifer Duffy put it:
It would be hard to accuse the Democratic frontrunners, Attorney General Jack Conway and Lt. Gov. Dan Mongiardo, of beating issues to death in their race for the nomination. Instead, they have battled on travel expenses and charges of eating crème brulee and drinking bottled water on the taxpayers’ dime. They have also taken aim at each other’s ethics. Even the NCAA men’s basketball tournament became a point of contention, albeit briefly.
Geography could be a big factor in the outcome. Mongiardo is from Eastern Kentucky, and is expected to do well there, while Conway is expected to win by a considerable margin in the Louisville area. Western Kentucky, which is up for grabs, could be crucial.
We won't have to wait very long before finding out the results; Kentucky's polls close at 6:00 p.m. local time, with the state divided between the eastern and central time zones.