Nate Cohn downplays the electoral consequences of today's decision:
If the Court had gone a different direction, the electoral consequences could have been more significant. But since the ruling preserves the status quo, the fundamentals of the health care debate remain essentially unaltered. Dissatisfaction with the health care law is already priced into the President’s approval ratings—Obama’s pursuit of health care reform was a defining element of his first term, and voters have already judged him on that basis. Opposition to the health care law was never driven by arcane constitutional concerns, even if many viewed it as government overreach.
Nate Silver echoes:
[B]e wary of whatever the polls say for the next week or two — the short-term reaction to the news of the ruling may not match its long-term political effects. As before, the presidential election is mostly likely to be contested mainly on economic grounds. Next week’s jobs report is likely to have a larger effect on the election than what the Supreme Court ruled on Thursday.