Jeb Bush is already confirming for us why he isn’t going to be the next Republican nominee:

With eyes increasingly on him, Jeb Bush signaled on Sunday the kind of campaign he would mount if he ran for president: one arguing against ideological purity tests while challenging party orthodoxy on issues like immigration and education.

There is nothing wrong with challenging the prevailing views in a political party, and it can sometimes be quite healthy. However, it is impossible to take Jeb Bush seriously as a candidate of dissent. If he ran, Bush would have substantial financial backing and the endorsement of quite a few party elites, and he would have their support because he passes their ideological litmus tests. Someone named Bush is unlikely to challenge entrenched interests of any kind, and on immigration he is taking the position that large businesses want. He isn’t really a dissenter from the party line, but rather the would-be enforcer of the one preferred by many party elites. Meanwhile, his views on his favorite issues have relatively weak support among voters in his party. Bush is also doing a spectacularly bad job of distinguishing himself from his brother, since immigration and education reform were two of George W. Bush’s pet issues when he first ran for president. As for this supposed aversion to “purity tests,” there is good reason to assume that Bush’s foreign policy arguments will rely heavily on trying to stigmatize and demonize dissenters inside the party just as his brother so often did.