Partisanship, when used in reference to politics, refers to the attitude of preferring and sticking to one’s own political party. In other words, the more that a person always takes the side of a given political party, the more partisan that person is.
The term “partisanship” is often used in a pejorative way. There are many people who feel that America has become too partisan in recent years. They sometimes use “partisanship” to refer to the practice of putting the good of one’s own party above the good of the country as a whole. For example, there have been stories in the media about Republicans in the House who did not want to vote for the recent bill that was meant to avoid the “fiscal cliff” because they thought that voting for it would hurt the Republican Party’s image. They felt that the law was necessary for the country and hoped it would pass, but did not want to vote for it because they felt such a vote would be bad for their own chances and those of their party.
However, partisanship does not have to be seen in this way. A person can be very partisan out of conviction, not out of self-interest. Partisanship is simply the practice of taking the side of your political party.