WASHINGTON - President Barack Obama says Congress' vote overturning his veto of Sept. 11 legislation was "a mistake" and "basically a political vote."

Obama also criticized some lawmakers, though none by name, for acknowledging they originally voted for the bill without knowing its contents.

Speaking during a CNN town hall event, Obama said he understands why the override happened, given the perceived political peril of voting against 9-11 families before an election.

But he says the right and harder thing to do would have been to let his veto stand.

Families of Sept. 11 victims will now be allowed to sue Saudi Arabia for its alleged backing of the attackers.

CNN released the clip of Obama's response to his first veto override hours before airing the full town hall Wednesday night.