Just like real voting, our system sucks because people vote expressively (for what they feel) rather than instrumentally (to accomplish policy).
What's "important" should be:
1. How big is the issue? The death penalty affects a trivial amount of people, the Obamacare fiasco a huge amount of people.
2. How can the issue be resolved? While I might sympathize more with those who suggest Global Warming is a huge problem, the proposed solution of cap and trade is terrible while the GOP of encouraging market responses seems practical. Likewise, many of the "problems" don't need solutions imposed by the government, because cultural and social dynamics will resolve them no matter who's in power (e.g. Gay rights).