Sneak Preview: Presidential Questions

Tonight, we're airing the inaugural piece in our series, "Presidential Questions." It's the first in a weekly series in which we'll show you the presidential candidates' answers to questions Katie asked them - both about their politics and about their character. If you saw our series, "Primary Questions," you'll recognize the format. Tune in tonight at 6:30 p.m. ET for the candidates' full answers. But for now, a taste:

Katie Couric: What one personal flaw do you think might hinder your ability to be president?

Sen. Barack Obama: I don't think ... there's a flaw that would hinder my ability ... to function as president. I think that all of us have things we need to improve.

Sen. John McCain: You know I'm not an objective observer. I think that would have to be to make sure that I don't make any decisions that are not fully informed by every source of information that's credible I can possibly get.