Editor’s note: Todd Graham is the director of debate at Southern Illinois University, Carbondale. He has coached his teams to national championships, and has been honored with the Ross K. Smith national debate coach of the year award. Graham has analyzed presidential debates for five elections.

(CNN) — In any debate, contestants must make decisions given their limited amount of time to speak. On Thursday night, Rick Perry made the wrong ones. The Texas governor came across as forced and all over the place — awkward, unsure, with no clear strategy for how to answer questions or when he should go on attack. At one point he tried to fit three attacks on his nearest challenger, former Massachusetts Gov. Mitt Romney, into one sentence.

In short, Perry misused his time.

Academic competitions set rules and speaking times, and the debate teams I coach cannot change them. Debaters must make argumentative decisions about what they need to say to win. You have to pick and choose your best argument and stick with it. You should have a theme, limit your attacks, clarify your positions. In the presidential debates, the candidates must also do so.

As we have learned by now, these debates are a bit stacked. Front-runners Romney and Perry get more questions, making the job harder for the other candidates. They have to win over voters with less speaking time. Some did well with their limited time at the Florida/Fox News/Google debate in Orlando, others not so much.

The newest debater, former New Mexico Gov. Gary Johnson, had the biggest challenge — I counted three questions directed to him. With almost no time to establish himself, the errors he made were magnified.

Sometimes a speaker’s delivery can be distracting enough to harm his or her content, and this was the case with Johnson. He twitched the thumb on his left hand nonstop, making him seem overly nervous. Seriously, I thought he was trying to challenge Ken Jennings for control of the board on “Jeopardy!” His fidgety, unsure manner, coupled with his newbie status, left a terrible first impression. Perhaps he was nervous, and maybe with more speaking time, Johnson would have been more comfortable. Unfortunately, based on Thursday night’s turn, I simply could not see him persuading anyone he should be president.

Rep. Ron Paul’s timing was off also. The Texan was asked how he would return powers to the states, and he explained he would veto all bills violating the 10th Amendment. Then he went silent. He had to be prompted by moderator Chris Wallace to use the 30 or 40 seconds he had left. You simply cannot leave time on the table in this format. While his continuation answer was better, Paul never got the chance to get rolling.

Herman Cain made the best use of his time. In one instance, he answered a question about what department he would cut if forced to do so. He explained why he would cut the Environmental Protection Agency. Then he continued, “Now with the rest of my time, could I offer a solution to Social Security?” He proceeded to explain his advocacy of the “Chilean model” and personal retirement accounts. It was a smart gambit on so many levels, but mainly because he moved the topic to an even more important one for voters.

Neither former Utah Gov. Jon Huntsman nor ex-House House Speaker Newt Gingrich had a net gain or loss from their use of limited speaking time. They should have followed the lead of Rep. Michele Bachmann of Minnesota or former Sen. Rick Santorum of Pennsylvania. At one point, Bachman interrupted and threw out an answer to a question when she was not the one being asked.

Santorum used extra time to attack Perry’s stance on border security relentlessly. Santorum repeatedly accused Perry of claiming to have already put boots on the ground and asked him why he was not doing a better job. Santorum repeated the question several times before the moderator finally cut him off. While both Bachmann and Santorum ran the risk of coming across as rude, they were effective. In future debates, these tactics might be many candidates’ only hope of getting more speaking time.

As for Romney, who went into the debate trailing Perry in polls, he used his speaking time pretty effectively. When Romney was attacked, he waited his turn, provided his answer or presented his plan to help the country and reminded the audience why he should be president. He deflected the sticky issue of his health care overhaul as governor in Massachusetts — considered his weakness with Republican voters — pretty well and was able to make headway on immigration. His attacks on Perry over immigration were effective because they were developed and thorough.

Contrast that with Perry. Sometimes Perry’s attacks seemed forced, out of place, with no sense of reason. One of them was so off topic that Romney actually said, “I thought we were on Social Security. …” This can hurt voters’ overall impression of Perry.

The other problem is that his attacks are not well-developed. Toward the end of the debate, Perry sleepily and awkwardly mentioned the Second Amendment, Roe v. Wade and Race to the Top all jumbled together in a sentence without explanation or setup.

These confused attacks prevented him from doing two things: First, Perry never selectively developed one of his attacks, so none of them stuck; and second, he did not use his time to advance his ideas. Perry needs to make better decisions on how to use speech time.

Argumentative choices are critical in this format. Like it or not, everyone must figure out how to get the most out of what speaking time they have. After all, if college debaters can be taught to set aside their favorite arguments and focus on making their best ones in the time they have available, then our presidential candidates should be able to do the same.

The opinions expressed in this commentary are solely those of Todd Graham