As an observer, primaries like the sort just concluded in Delaware are incredibly amusing. It’s an opportunity to see bloggers, reporters and flacks who’ve never won anything anywhere declare emphatically that someone will definitely or can’t possibly win in a state they’ve never run a campaign in, and in some of the more absurd cases, have never even been to. The best part is, a lot of these folks end up getting on television and talking about it, intoning with certainty like the blind men and the elephant. And they get paid to do it! (I love America.)

Amateurs like to read tea leaves and polling data to devise predictions. In a conventional political year, this might give you some degree of accuracy — but in a year like this, as we’ve seen, it’s about as much of a sure thing as having a grizzly bear pick your fantasy football team. So when Karl Rove said she couldn’t win, even as my politically moderate relatives told me they liked Christine O’Donnell, I put a heavier weight on their opinion. After all, the people saying this — unlike Rove, Kristol, and scads of other observers who’ve blatantly carried water for Castle over the past few weeks — actually live and vote in Delaware. It seemed like a stretch to me, but I trusted the bear, and I got Arian Foster in the 12th round. Shows me what I know.

Some of these consultants and flacks conceded any pretense to ideological conservatism long ago. Yet some political observers who are smart and respectable — RS’s own Dan McLaughlin is one of these — have ended up at the view that a guy like Mike Castle needed to win. Dan’s post is as fine a thing as you can read on the matter. I also think it’s wrong.

Here’s my view: Conservatives should not tolerate the likes of Mike Castle because of the simple fact that a 51 member Senate with Mike Castle is a Senate where Mike Castle is the most important vote in the room. As Specter and others before him, that Senator will set the terms of policy debates, determining in advance what can succeed and fail. Those who advance the argument that a majority with Castle is better than being in the minority tend to place priorities on Senate committee chairmanships and staff ratios and lobbyist cash… a list which pales in comparison to the power they would wield as the broker for both sides. Again and again I saw this play out during my time as a Senate staffer, and anyone who tells you contrary is incredibly naive about the way legislative decisions are made.

As a friend of mine in the business of campaigns and elections has said, electing moderates simply to secure a majority for Republicans is a self-defeating proposition. We’ve seen this play out time and again. Career politicians abhor principle, and adore power and fecklessness. Their presence in Washington provides constant aid and comfort to the Left. They dilute the brand, confuse voters and sell out conservatives just at the moment they are needed most.

It’s not about being right rather than winning, it’s about the definition of winning in the long term, which cannot be done with elected politicians who don’t believe in conservatism.

In the end, it’s really that simple.

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