smooth, the US isn't the first country to have people in their 70s or even 80s in office, run for office. The point isn't generalizable from the small data set you're considering. I agree that Reagan was showing signs of Alzheimer's setting in toward the end of his second term, but surely you know that aging is highly idiosyncratic. McCain's mother is 96 y.o. and still very vigorous. In fact, (under the heading of "hilarious stuff") I saw a posting somewhere (I forget where) with the title "who is older?" Underneath were two pictures - McCain's 96-y.o.-mother and Keith Richards. And McCain's mom looked much better.
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Oh, and ASU, if you read through the rest of her comments, she actually was careful not to commit to a military approach, only that it shouldn't be off the table. I'll grant you that she isn't fluid yet on foreign policy, and that she was to a large extent spitting back stuff she had memorized.