One of the weaknesses of our Senate forecasting model is that, for all the precision we apply to the general election forecasts, we only eyeball the primaries, making estimates about the likelihood of each potential matchup on the basis of the polling and other factors. Nevertheless, we try to be pretty careful. For instance, we had assigned a 25 percent likelihood that Joe Miller would defeat the Republican incumbent, Lisa Murkowski, in Alaska, as happened. We had also assigned small likelihoods to a number of other outcomes that did not come to fruition, like J.D. Hayworth ousting John McCain in Arizona (Mr. McCain won by 24 points) or Chet D. Traylor unseating David Vitter in Louisiana (Mr. Vitter won by 81).
But in the case of Christine O’Donnell, who defeated Michael N. Castle in the Republican Senate primary in Delaware last night, it hadn’t even occurred to me to add that possibility to the model until a few weeks ago. Mr. Castle had been elected statewide 12 times — twice as governor, once as lieutenant governor and nine times as Delaware’s at-large United States representative. Ms. O’Donnell had run for Senate twice before — in the Republican primary in 2006 and in the general election in 2008 — and lost badly both times.
I’m not saying that we would have carefully considered Ms. O’Donnell’s case and assigned it zero probability. Rather, it wasn’t something I had thought about at all — in the same way that one doesn’t think about a strong earthquake occurring unless one lives in California.
In fairness, primary elections can have a self-fulfilling quality to them, and until Mr. Miller beat Ms. Murkowski in Alaska three weeks ago, Ms. O’Donnell probably wasn’t on the minds of a lot of voters either. Ms. O’Donnell’s major endorsements, like that from Sarah Palin, came late in the race; before that, some key conservative groups like FreedomWorks had deliberately declined to endorse her, fearing that she wasn’t electable.
Nevetheless, Ms. O’Donnell’s victory — like Scott Brown’s in Massachusetts this year, or Hillary Rodham Clinton’s in the New Hampshire primary two years ago — was an emphatic reminder that voters write the script. The rest of us self-proclaimed political professionals – journalists and pollsters, activists and bundlers, lobbyists and party-leaders, presidents and senators — are just the stagehands.
So what does this mean as we head into November — and beyond?
There are some fairly tangible conclusions. For instance, Ms. O’Donnell’s win almost certainly reduces the possibility of a Republican takeover of the Senate. She could still defeat the Democrat in the race, Chris Coons — as Mr. Castle could have lost to him. But on the basis of the polling (and here we are, thankfully, again on solid empirical ground) the Republicans went from being extremely likely to win the race to extremely likely to lose it. They may now need to bring another state like Connecticut or West Virginia into play to have a decent chance of taking the Senate; indeed, I would expect to hear a lot of chatter about opportunities like these, as the Republican establishment seems ready to concede Delaware.
Another conclusion, of course, is that the Tea Party is a mixed blessing for the Republicans. Undoubtedly, in my view, they have done the party more good than harm over the past year and a half, bringing it back from what pundits assumed was the brink of irrelevance (but may instead just have been the nadir of a political cycle), to a position where they are poised to make electoral gains that could rival or exceed 1994.
But in order to achieve those gains — not a fairly ordinary gain of 20, 30 or even 40 House seats, but the earth-shattering, upside results that Republicans are dreaming about — they will need for three basic things to happen. First, they will need a solid majority of independent voters to select their candidates. Second, they will need the Democratic base to be uninterested in the election. And third, they will need their own base to be enthused.