Not hard to connect these dots: Rick Perry does poorly in last debate, then Herman Cain wins Florida straw poll in shocking upset.

So here’s the obvious thing about running for president that sometimes gets lost on candidates: It’s hard. Really, really hard. There are so many challenges, and when they accumulate, it just overwhelms and sinks campaigns.

On top of putting together a campaign, which is like creating a major corporation overnight, building a field organization, announcing and defining your candidacy, scheduling stops across the country, and raising money, you have to go out and debate. And you’d better be ready. As Rick Perry has discovered.

There are three opportunities during a presidential campaign when you can really change the dynamic and move the needle: your announcement, the convention nominating speech and selection of your vice president ticket, and the debates.

Debates require a lot of hard work and preparation. If you try to wing it, it shows. I gave Governor Perry a pass on his first debate. But I was really surprised at his second debate. And shocked by his third. Because he showed no improvement. At all. He should never have been surprised by questions on social security, illegal immigration, and HPV vaccinations. But he responded like he was hearing the questions for the first time. Even the third time he was asked.

The debates proved how difficult it is to announce a national campaign for president late on the calendar, especially having never run before, and enter into a scramble of debates right out of the gate. I understand that the Perry campaign is completely overwhelmed. But it was his choice to jump in when he did. What I don’t understand and can’t excuse is why is he wasn’t better prepared by his third debate. He should have shelved everything on his calendar to make sure he was ready.

In 1999, George W. Bush started practicing for debates six months ahead of time. Dick Cheney was maniacal in his debate preparation, and it showed. Even rehearsing at the same time the debate would be held and at a similar room temperature. And Stuart Stevens, who helped Cheney prepare for those debates, and who had similar convictions about the need for preparation, is now working with Mitt Romney. And it shows.

Perry can recover, but he has wasted some huge opportunities, making it a lot harder on himself and his campaign than it should have been. He’s raised a lot of concern among Republicans about whether he is up to the job. He’s started new conversations about Chris Christie and Sarah Palin. And he’s given Rick Santorum, Michele Bachmann, Ron Paul, perhaps Romney, but especially Herman Cain an opportunity to take advantage in Iowa.

So maybe now we know why Governor Perry’s grades at Texas A&M University were less than stellar—lack of preparation. When your team is going up against the captain of the debate team, against the guy who’s been practicing in front of the mirror morning, noon, and night for the last five years, you think you’d get in a bit more practice. Especially when it’s not just your future but the future of the nation at stake.

Running for president is hard. But it’s good preparation. Because being president is a lot harder.