GEORGE STEPHANOPOULOS, ABC NEWS: Ted Cruz just said -- Ted Cruz said this is time for the circus, I think, is over right now.



Does it make the debate on the Republican side somewhat more serious, help any particular candidate?



BILL KRISTOL: Yes, look, there are two things a president does that he does uniquely. He nominates judges and is commander-in-chief. Health care, education policy, tax policy, Congress plays a huge role.



I think the president -- the presidential debate on the Republican side, the choice will now focus much more on who will put good judges on the Supreme Court, who has the knowledge and -- and the temperament and the -- and the background where voters can be confident that they'll get good conservative constitutional judges.



And the commander-in-chief issue, which Donald Trump raised central -- squarely last night by saying that George Bush knowingly lied us into the war in Iraq. The Republican primary -- it's one thing to say the war was a mistake, knowingly lied us into the war in Iraq?



Are Republican primary voters going to accept this?



I believe that Donald Trump's candidacy was dealt -- and I said this before and I've been wrong -- but I really do believe last night could be a moment where finally Republican voters say enough -- enough with the being in, you know, engaged. Trump's interesting. He's saying some things I like. He's sticking it to those politicians.



And finally, maybe people will focus on can and should he be president of the United States?



And I think Republican primary voters will say no.