If the Gods had intended Politicians to think....
The common sense answer to this would be, Higher IQ = Better leadership. But Steve Sailer of VDARE.com shows that this may not always be the case.
(...)Still, this doesn't mean that IQ is not desirable in a President, all else being equal. The problem is that all else is not equal. There are so few people at the far right end of the IQ bell curve that you can't always find amongst them all the other Presidential talents you need.The article also contains a lot of other fascinating facts, like the "intellectual" John F Kennedy scored 119 in an IQ test he took. The "boorish" Richard M Nixon, by contrast, is said to have an IQ of 143.
In contrast, the rare individuals who make it to the White House from the fat part of the bell curve are far more gifted overall than is typical for their IQ. It's the same as with height in basketball. If you are 7'6" tall, NBA teams will throw money at you no matter how dorky you might be. But if you are only 6'0", the competition is so fierce that you need to be as quick as Allen Iverson.
You can read this truly fascinating article here. Unfortunately, it deals only with US Presidents and Presidential candidates. I'm sure such an analysis of Indian politicians would be quite enlightening.
Hat Tip: Half Sigma.
PS: Steve Sailer performed a quantitative analysis of Bush and Kerry's test score before the elections (and the Globe revelations) and found Bush to be marginally smarter than Kerry. Read his I-told-you-so post here.