Eisenhower reputedly said "God help this country when someone sits in this chair who doesn't know the military as well as I do."
Many conservatives are excited by the brilliance of Ted Cruz. Before he dropped out, Jindal was his only competition on the IQ scale.
If the nomination comes down to Cruz or Rubio, both men are quality candidates. Much better than in previous election cycles.
However, brilliance is overrated. Obviously, there are some professions where that's a big plus, like math and science. But even in that case, the tortoise sometimes outperforms the hare. Linus Pauling was a genius; James Watson was a plodder. But it was Watson, not Pauling, who discovered the Double Helix.
In politics, Newt Gingrich is a brilliant man, but a failed leader as Speaker of the House.
Robert McNamara and McGeorge Bundy were supersmart, but they gave poor advice on how to prosecute a war.
Richard Perle, Paul Wolfowitz, Bill Kristol, Charles Krauthammer, Michael Rubin, Donald Rumsfeld, and Dick Cheney are very bright guys, but they don't know how to win wars–or what to cut their losses.
They have the wrong kind of intelligence and/or the wrong kind of experience. Too abstract. A large part of winning wars is knowing which wars to avoid. Avoid getting into wars you can't win.
Brilliance can be a snare if it makes you overconfident in what you can achieve. Especially in foreign policy, there are many variables beyond the control of any president. Brilliance isn't the first thing I look for in a presidential candidate.