But the proposal isn't to change the capital gains tax rate. It's something that would only apply to people making a million dollars or more.
And really, people who do that, and aren't being payed a regular salary are essentially disguising regular income as capital gains. They should be taxed at the max income tax rate for their income.
I think the "Warren Buffet rule" approach would resolve the problem without the problems that just increasing the capital gains tax would add. With the inequity in tax rates, people who do investing for a living have an incentive to define their income as capital gains. While raising the capital gains rate across the board would address that problem, it would also cause all the problems conservatives point to (discourage investment, cause problems for some people selling their homes, etc.)
Obama's proposal, it seems to me, is a pretty focused solution, that seems to me to be a no-brainer.