http://www.slate.com/articles/news_and_politics/politics/2015/09/donald_trump_is_a_test_for_all_republican_presidential_candidates_how_they.html

Jeb Bush has decided to stoop to conquer. The onetime GOP front-runner didn't think Donald Trump was worth his time. By simply being the adult in the race, he hoped, voters would stick with him and turn away from Trump. Or, at the very least, voters would ignore Trump’s trolling of Bush. But the decent opinions of mankind did not kick in. Bush's poll numbers dropped, while Trump’s rose. Now Bush is confronting Trump head-on. “Donald Trump is trying to insult his way to the presidency,” Bush said Thursday. Bush is also picking up the frequency of his assaults, taking on Trump in ads, with an online quiz about his liberal past, on Instagram, and in television appearances. “Trump is wrong for the party and the country,” said a Bush aide. “We are going to fight for it. Ducking and hoping he goes away is not a path to success.”