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

Scott Walker was the perfect candidate on paper. He had no shortage of credentials to run through in his appeals to Republican donors and voters alike. Political observers are beyond familiar with them by now, but—in a last tribute to the second major presidential candidate to drop out of the herd—let’s run through his resume one final time: Three gubernatorial victories in four years in blue Wisconsin; a record of meaningful ideological accomplishment in the face of protests that swept up the nation; an appeal broad enough to stretch from social conservatives to libertarian-leaners like the Koch brothers to more traditional Republican establishmentarians.