I'm saddened to hear of Scalia's death, and I think its worth reflecting on who he was. *Of course* I disagree with Scalia on a bunch of social issues, but there is more to him then that. I'm linking an informative post by law professor Ilya Somin, but I have a few remarks of my own.
Scalia had a huge intellectual impact on Constitutional interpretation through his advocacy of "textualist originalism" - which is the idea that we should read the text of the Constitution from the perspective of how common people living in the time it was adopted would have read it. The purpose of this idea is to enable Americans to have more common ground about what the Constitution means - to narrow the disagreements that we have about its meaning, and move us more toward talking about whether or not we agree with what it says, instead of talking about whether or not we agree about what it means.
I don't think textualist originalism is always the right way to read the Constitution. For example, I don't think "cruel and unusual" should be read from an 18th century point of view. However, I do think its an incredibly useful point of view, and that it is often the right point of view. It is also not a point of view that always leads to conclusions that are in line with the views of modern Conservatives, and Liberals who think Scalia inerrantly opposed them do so out of ignorance. For example, in Hamdi v. Rumsfeld, Scalia joined Justice Stevens in opposition to the detention of a U.S. Citizen without trial.
Ultimately, "textualist originalism" is an idea that is leading us toward more rigor in how we think about the Constitution, and it has prompted important and useful liberal responses, such as Jack Balkin's "Living Originalism" and Breyer's "Active Liberty."
Scalia's death may have a big impact on the upcoming political contest. The Republicans need a galvanizing issue like a Supreme Court vacancy in order to get their fractured constituents to come together behind whatever candidate they nominate, and for that reason, they'll fight any nominee the President puts forth. Likewise, the Democrats have an opportunity to change the balance that the Supreme Court has had since the Reagan era, in favor of their points of view. Unfortunately, I fear this event will result in a year of really really nasty partisan fighting.