What is party identification, and why is it important? How do political parties make use of it?

What will be an ideal response?

An ideal response will:
1, Explain that party identification is the sense of belonging to one party or another and that most Americans identify with either the Republican Party or the Democratic Party.
2, Describe how party identification is important because it shapes how a person feels about a wide range of public issues, how likely that person is to vote, and which candidates the person will vote for.
3, Discuss how the parties make use of party identification by first "rallying the base" of their core supporters for votes, campaign contributions, and activists to work for them—increasingly through focusing on issues and symbolic gestures—and then try to win supporters among the swing voters.
4, Mention that because the parties have been running so close among those who identify with one or the other party, attracting the "leaners" or swing voters has become increasingly important to winning elections, and showing a strong base is one way of doing that.