Question about political capital.

It seems in the beginning I get as much as I want. But around 2nd term I seem to be capped at about 21. Why? I mean my advisors were pissed off at me but I’d go a few rounds not doing a thing and my points wouldn’t carry over. Why, I ask!

That sounds like the political honeymoon option is kicking in. Basically you get much more political capital when you are first elected, and over time, as you stay in power, this slides down to around half what it was right at the beginning.
If you don’t like this option, it can be turned off under the options screen. It should have immediate effect (even mid-game).