Had things gone just slightly different on 14 October, 1912 in Milwaukee, Taft wouldn't have needed to have campaigned particularly hard. Why it's almost as if he knew in advance....
Oh, now, don't go spreading rumors.
What gets confused is the party and the national campaigns. Taft campaigned vigorously in the Spring primary. Roosevelt won most of the popularity contests (the big exception was Massachusetts, which Taft won in his most vigorous effort, and which secured for him the delegate totals he needed for the convention). But not all the primaries were open, and in open primaries, not all the delegates were elected. It was the first primary ever, and it was very confused. Notably, turnout was low, which meant that the motivated voters voted, securing an influence beyond their numbers (sound familiar?)
After the June convention, Taft's only major public speech was at the party notification in July at the White House. After Congress finally closed out, he went to Massachusetts and enjoyed himself the rest of the summer and autumn. Roosevelt and Wilson hit the trail. Taft played golf.
He actually did pretty well. Roosevelt had offended too many people, and Taft held the party too strongly. The Republicans won a couple August preliminaries that looked good for Taft. Bookies started giving Taft better odds. But after the shooting, a shocked public moved its sympathy to Roosevelt. Giving that speech with a bullet in his chest was an amazing publicity stunt. Whatever the heroics of the act, it got him votes.
By then, Taft knew Wilson would win, and he was content with having defeated Roosevelt. It's all in the book...
And thanks for your encouragement on that. Ok. Back to work!
*He pinked me! Don't harm him, bring him up here. I want to get a good look at him...*
--T.R., 14 October 1912, Milwaukee.