You can't beat a man who refuses to admit defeat. You can kill a man like that, but you cannot defeat him otherwise, because he has gotten it in his mind to keep fighting, whatever happens.
Here's the other part of that equation:
You can't win a battle until you are willing to fight one.
That is why Lincoln fired McClellan and backed Grant to the hilt.
Of course, it is wise to choose the right battles. Often, though, the "right battle" is evident only in retrospect. Waterloo marks Napoleon's downfall only because Wellington won. Before he could win he first had to fight. Ditto Nimitz at Midway and Gualcanal.
Before you can win you have to fight. Rarely are opponents so accommodating that they give battle where their defeat is foreordained.
Although, come to think of it, a sixty-year old pervert making jokes about the rape of a fourteen year old girl comes pretty close.
John Keegan traces the rise of U. S. Grant and the Union victory to the night after the first day of Shiloh. Grant's forces had been defeated and many units were routed. That was nothing special; it was pretty much SOP for the Union in the first year of the war. What set Grant apart was what he did next.
Instead of accepting defeat and retreating, Grant resolved to stand and fight the next day. His "beaten" army won a smashing victory. Thanks to Grant, and Grant alone, Shiloh did not become another Confederate victory like Manassas, Chancellorsville , or the Seven Days.
Reagan's victory in 1980 was not inevitable. Without North Carolina and Texas in 1976, Reagan's career would have ended as a two-term governor of California and a defeated presidential candidate who never came close to the nomination.
Why are so many right-wing pundits afraid of a good fight? McCain argues for an ambitious careerism and there is truth in that. I'd suggest that three other factors enter in as well: fear of failure, fear of ridicule, fear of boredom.
You can only fail if you first try. If you can dream up enough clever excuses, you can avoid trying to accomplish anything.
Defending Sarah Palin or Rush Limbaugh is dangerous. There is always the chance that the People Who Really Matter will turn their scorn on those who dare to defend the indefensible. What self-respecting pundit wants to be called a "ditto-head" or accused of being a humorless puritan?
Peter Drucker wrote in his memoirs that every time he saw something accomplished it was by "a monomaniac with a mission." Everything in my experience supports that observation. Only a monomaniac has the intestinal fortitude to persevere, Outside opposition is the smaller part of the problem. Much larger is the human desire to put aside hard, boring work and do something more fun, more interesting, easier, different.