Obama has played rough politics. But he has done it better than Clinton. Which is another reason to support him.
Some people want their politics to be pure. They are naive, at best. Politics is never pure. Politics is War by other means. You don't win without getting bloody.
The secret to a successful political system is not purity but being able to put the political guns aside when the political race is over and it is time to govern. What has distinguished the Republicans from the Democrats in recent years is that the Republicans keep the political guns cocked even after the race is over while the Democrats unilaterally disarm even during the political race.
We need to return to a separation of politics from governing. But we won't achieve that by either purity or endless political warfare.
I think both Obama and Clinton would agree with that assessment. I just also think that Obama is demonstrating more finesse in handling the political side. How he handles the governing side remains to be seen.