Thomas Sowell doesn’t like talk of Romney’s inevitability:

Inevitability has a very unreliable track record. Within living memory, totalitarianism was considered to be “the wave of the future.” During the primary season, people should vote for whomever they prefer, on their own merits, not because pundits have pronounced them inevitable.

Sowell is confusing two very different things here. When I refer to Romney’s dreadful inevitability, for example, this certainly isn’t an endorsement of Romney or an instruction on how people should vote, nor is it a prediction that he will win in the fall. It is an acknowledgment that he has the most effective organization and fundraising to compete everywhere in the country. It recognizes that he appeals to a relatively larger part of the Republican electorate than any of his rivals, and for that reason he will continue to win far more delegates than any other candidate seeking the nomination. Republican voters are voting for the candidate they prefer, and the candidate that enough of them have been voting for unfortunately happens to be Romney. Romney’s inevitability as the nominee is a function of his weak competition, but it is also the result of Romney’s many years of preparation for this contest, including his previous failed attempt in 2007-08.

One of the reasons that his competition is so weak is that very few of his rivals started preparing for this contest before 2011, and many of them counted on Romney’s unacceptability to do half of their work for them. Almost all of the more conservative candidates have run their campaigns on the assumption that all they need to do is show up, and then the natural anti-Romney reaction will lift them to victory. Speculation about the fantasy candidates has relied on a similar assumption: conservatives just need the right person to rally around, so all that is needed to change the outcome is to persuade one of the fantasy candidates to enter the race.

Later on, Sowell offers a questionable theory to explain how challengers can defeat incumbent Presidents:

How does anyone ever defeat a sitting president then? They do it because they have a message that rings and resonates. The last Republican to defeat a sitting president was Ronald Reagan. He was the only Republican to do so in the 20th century.

Sowell mentions that Reagan was the only Republican to defeat a sitting Democratic President, and then concludes that this was because Reagan “took the fight to Carter,” but this overlooks the fact that there haven’t been very many sitting Democratic Presidents to run against in the last sixty years. In the post-war era, two out of four sitting Democratic Presidents rejected the option of running again because of the enormous unpopularity of Korea and the unfolding disaster in Vietnam. Reagan was the only Republican to unseat a sitting President partly because there have been so few sitting Democratic Presidents seeking re-election since FDR, and the only other opportunity to defeat a sitting Democratic President in the 20th century before FDR was the election of 1916.

It obviously never hurts to have an appealing message, but Sowell’s claim isn’t correct. In order for incumbents to lose presidential elections, they must not only be perceived as having failed, but economic and/or international conditions have to be poor. The poor conditions make a challenger’s message resonate. Absent poor conditions, a challenger might have a very bold message that theoretically ought to be appealing, but it will not be enough to persuade most voters to support the challenger. After all, the main decision that voters are making is not whether they want to endorse the challenger’s vision, but whether they want to throw out the incumbent. The election is not going to turn on the Republican nominee’s ability to condemn the individual mandate with zeal and credibility.