Don't states like their sons anymore?

No, I'm not going to write about family dysfunction. This post is instead about an extinct political species that was known as the "favorite son". A favorite son was a political leader in a state (often a governor or senator) who secured pledges from delegates in his (usually male; Senator Margaret Chase Smith, Republican of Maine, made history in 1964 by becoming the first favorite-daughter candidate) state to vote for him for president, at least on the first ballot, at his party's national convention.

The favorite-son candidate would not campaign outside his home state. His only chance of winning the nomination would be in the event of a convention deadlock where no one candidate got an overall majority (or two-thirds majority in cases where the rules so required) of the vote on early ballots. In those circumstances, the party might turn to a dark-horse candidate, and the favorite-son candidates would be obvious possibilities for that role.

Also, the existence of favorite-son candidacies would contribute toward producing a convention deadlock. With several states' delegations not voting for the "real" candidates, it was more difficult for those candidates to put together a majority (or super-majority) of the votes on early ballots.

Alternatively, a favorite-son candidate might belatedly endorse one of the front-running candidates, and induce his delegate supporters to follow suit. A bargain might be struck, to exchange such an endorsement for consideration on policy issues or appointments.

The concept of the favorite-son candidacy quickly faded into history after 1968. It is out of synch with the paradigm that currently governs the delegate-selection process in both parties, that the voters should determine the outcome of a nomination by electing delegates, whether via primaries or caucuses, who are committed to voting at the convention for whichever candidate is favored by the voters who elected those delegates.

However, here is a New York Times article, speculating on the possibility of a favorite-son candidacy (which in the event did not come about) as late as 1988.