Being from the UK I can’t claim to be very familiar with American politics but I assume that Scalia’s main point is that decisions such as the decision on gay marriage should be made by the population. That is what democracy is. A population governing itself. Scalia is apparently suggesting that the Supreme Court might represent a population being governed, not by themselves, but by the nine judges. I don’t know who elects them but it can’t be a true representation of democracy. I’m not saying if it’s a good thing or a bad thing because I’m not sure but it’s not democratic.