In a perfect world, people could approach elections planning to vote for whomever best represented their views. It wouldn’t matter whether the candidate was a Democrat, Republican or communist–so long as the most intelligent and honest candidate made it to Capitol Hill, all would be well in the world.

Unfortunately, we don’t live in a perfect world. And in our imperfect world, a candidate’s party affiliation matters.

Many decry those who vote “straight ticket,” or simply selecting candidates with the proper letter (R or D) next to their names. But to believe that you can vote solely for an individual is na’ve. Some of the most important votes a member of Congress ever casts will not be for nominations or bills or resolutions. They will be cast behind closed doors, and they will define Congressional leadership for the next two years.

The party that holds the majority in the House of Representatives or Senate decides whom the speaker or leader is. That individual sets the agenda for the Congress–effectively meaning that the party in charge decides what votes get placed on the agenda when Congress breaks for recess and other administrative details.

More importantly, while both parties get to select members for various committee assignments–judiciary, intelligence, appropriations, foreign relations, etc.–the majority party gets more of its members on those committees, and it decides who holds the chairmanship.

Realistically, the makeup of those leadership positions is more important than any individual vote a member of Congress will cast during his or her tenure as a public official. The party with the majority sets the agenda, controls the committees and is in the best position to choose when compromises are forged. In other words, Congressional leadership decides whether time is spent debating dead-end Constitutional amendments and if divergent legislation about issues like immigration reform can get resolved between the House and Senate.

To a member of Congress, an individual vote on an individual issue is a drop in the bucket. His or her warm body sitting on one side of the aisle or the other defines what the bucket looks like, where it’s located and what we’re filling it with.

When Joe Lieberman lost his primary race to Ned Lamont, D-Conn., in Connecticut this summer, it didn’t matter that Lieberman was a good senator who came “this close” to being vice president of the United States. Prominent Democrats such as Charles Schumer, D-N.Y., and Hillary Clinton, D-N.Y., threw their support behind Lamont and denounced Lieberman’s decision to run as an independent.

These Democrats weren’t being callous, nor were they disregarding Lieberman’s qualifications–they were simply being practical. More important than who is better for the job is whether the seat for Connecticut turns blue or red on Nov. 7.

This pragmatism is found on both sides of the aisle. While I was interning for the Senate Judiciary Committee this summer, I heard staff members criticize a certain Republican senator. They had nothing good to say about his work ethic or intelligence–and in the next breath, one of them said, “If I didn’t care about the majority, I’d want him to lose his race.”

So while it would be nice to have the most intelligent and honest people running the country, ultimately, that’s just a perk. Given the choice between a stalwart member of the opposition and a painted rock being elected, many would choose the rock–given it was painted the right color, that is. And that’s not an unethical choice. It’s a logical choice.

Most people describe themselves as moderates, regardless of their actual party affiliations. Most Americans admire so-called mavericks who cross party lines, reach across the aisle and forge working relationships.

But in the end, every candidate belongs to the party that he or she believes in–the party that offered him or her financial and other support throughout the campaign. And when it comes time to vote for speaker of the house or senate majority leader, it won’t matter how “moderate” or “nonpartisan” that individual is at heart. The only thing that will matter is which party he or she is conferencing with. Legislators might cast their weight behind like-minded moderates within their own party, but “in their own party” are the key words here.

The fact is, while we may live in Purple America, Congressional leadership can only be blue or red.