Why are there more teams in the National League than the American League?

So "interleague play" isn't daily and every team can play a game. Otherwise, there would either be one team from each league that doesn't play or an odd number of interleague games would occur.

There are 30 teams. If the two leagues were equal, they would each have an odd number of teams. Then you would have to have at least one interleague series going on at any given time, which would make scheduling a nightmare.

Correction

The above s are good in theory, however, the NL has 16 teams and the AL teams have 14 teams because in 1998 the Milwaukee Brewers agreed to move from the AL Central to the NL Central so each team league wouldn't have 15 teams, causing 1 team to have to be idle every day, extending out the season and making travel and scheduling much more difficult. Before 1998 which is when the addition of the Arizona Diamondbacks to the NL and Tampa Bay Rays to the AL took place, each league had 14 teams, and this wasnt a problem. The move of the Brewers had nothing to do with "interleague play", as "interleague play started in 1997 and the change took place in 1998.

Actually the change had everything to do with interleague play. With 15 teams in each league, there would have had to have been at least one interleague series going on at all times. MLB didn't want that. They only wanted interleague to happen during the middle of the season. The fact that interleague play had already started is irrelevant.