For various reasons. Scandals, clothing expenses, qualifications?
Well, it happened to the Democrats, back in 1972.
Democratic presidential candidate George McGovern picked Senator Eagleton for his running mate in 1972. Later it was discovered, Eagleton was taking medication for a psychological problem. Campaign handlers would say "some mental illness liabilities" even if the problem wasn't real serious.
McGovern had to "reluctantly," I guess, drop Eagleton from the ticket and run with someone named Sargent Shriver.
That's my look down memory lane.
Democratic party was embarrassed by this turn of events. Laundry out in the open.
McGovern lost "big time" to Nixon in November of 72. Watergate wasn't "big time" in the public lexicon yet.
Republicans often have a smoother looking machine.
In some ways, Sarah Palin is refreshing for being outside the box. Reminds me of someone one might meet working behind a lunch counter in Minot, North Dakota or somewhere. Refreshing in style, but not necessarily in substance, unless one is a conservative.
I doubt they'll drop Palin, this late in the game.
Since there was consternation among Democrats in 72 over a vice presidential pick, same thing can happen to Republicans.
Oh, I forget, Dan Quayle.
I'll admit, I couldn't spell potato if I didn't have spell checker.