The Court is empowered to throw out unconstitutional legislation. It is not empowered to throw out Constitutional legislation that happens to be a bad idea.
[1] On everything from campaign finance to drone strikes, nobody bothers drawing the very important distinction between "bad idea" and "unconstitutional."
If we want to be in control of our own governance, we would be better served if elected Congressmen make the laws rather than nine old people who are accountable to no one (even if those nine old people are brilliant thinkers).
More generally, I'm quite wary of situations in which the Court second-guesses Congress. Every time the Court does so, it uses up some of the Court's political capital, which is ultimately the only thing the Court has to enforce its judgments. Even though I'm a liberal, I tend to be very skeptical of judicial activism because I think that political capital should be saved for when it is really necessary.
(According to insiders from the administration, Bush thought the campaign finance law he signed was unconstitutional, but he punted the unpopular job to the Supremes.)