Things that are political have to do with government, elections, and how society is run. Congress, state representatives, even county council members are all part of our political system.
The Republicans and Democrats are the two main political parties in America — they support political candidates that run for office. The major things that politicians discuss, like balancing the budget, raising taxes, and immigration laws, are political issues. But if someone gets a promotion just because they're friends with the boss, you'd also say it was totally political. In other words, they got ahead because of their connections rather than their qualifications, just like a lot of politicians.