Its possible, but the stupidity that's being demonstrated by Palin and McCain suggests they don't believe you.
McCain is far from a "rare hero". His story is the story of millions of ordinary Americans who served over the years with the exception that 99.9 percent of those Americans never had a head start like McCain. To compare McCain to Washington, Eisenhower or Grant is a joke. Those men were inspirational leaders, John McCain is nothing of the sort.
I consider my father, who at 19 years old jumped out of planes into France and Holland and later wound up in Belgium where he had a nice chunk of flesh torn off his right leg, much more of a hero than McCain. My father came from nothing, vounteered to fight the nazis, after the war went to college, then graduate school and went on to have a very successful career. He's 83 now and in perfect shape for a man his age and he would never consider bragging about his accomplishments. He did all this on his own, without the help of connections and protections that weren't available to him.
The first time I voted was 1980, the year I turned 18. Never in all that time have I seen a serious candidate resort to the twisted, hateful, garbage that McCain is now attempting. He is an embarassment to himself and makes Bush look like a choirboy.
If you think McCain has more experience that's fine. That's a 100% legitimate reason for you, not that you need to justify your vote. I believe, however, that he clearly doesn't have more competence or character than Obama. At one time he appeared to be a man of honor, he is now a common hack.
I'll have to take the word of my next door neighbor who was a year behind McCain at the USNA. His wife and McCain's first wife were close friends. He's not voting for McCain. Neither is my father.
Good luck with the important exercise of your right (and duty) to vote.