MICHAEL BARONE: Old rules won’t determine GOP presidential candidate.

The weakest part of our political system, by a considerable margin, is the presidential nominating process. It tends to exclude from consideration those with the greatest experience in what is uniquely the president’s responsibility, foreign policy and military strategy.

It tends less strongly to exclude members of Congress, particularly House members but also senators, whose extensive voting records inevitably contain material that is politically damaging at some point in the process. The process has become so lengthy that candidates often come up with strategies and programs that are rendered obsolete by the time of the next presidential inauguration.

All that said, we are stuck with it — or stuck with the version of the schedule that the national Democratic and Republican parties, acting for once in concert, and the various state parties and state legislatures can agree on.

So it may be worthwhile, before trying to assess the chances of likely, putative and possible Republican candidates in the 2012 cycle, to dismiss some of the rules of thumb that have arisen over the years.

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