Patricia O'Toole: T.R. failed in his brash bid to regain the White House, but his Bull Moose Party pushed ideas that would animate the century

When Theodore Roosevelt challenged William Howard Taft for the Republican presidential nomination in 1912, few cheered. Enemies accused him of monumental egotism, and most admirers, foreseeing his defeat, were worried that posterity would frown on his quest for an unprecedented third term. But as Roosevelt saw it, he had to involve himself. He had left the White House in 1909 with the expectation that Taft, his good friend and chosen successor, would continue on the progressive course set by the Roosevelt Administration. Instead, Taft had filled his Cabinet with corporate lawyers, bungled a chance to overhaul an antiquated tariff that enriched manufacturers at consumers' expense and undermined Roosevelt's farsighted environmentalism. Taft means well, Roosevelt would say, "but he means well feebly."

Then came the midterm elections of 1910. The G.O.P. lost control of the House, and Roosevelt began criticizing Taft's policies in print. The final rupture occurred a year later when Taft's Attorney General filed an antitrust suit against the U.S. Steel Corp. because of a 1907 acquisition that Roosevelt had personally approved. T.R. was outraged. The decision to challenge Taft soon followed. T.R.'s campaign would not succeed, but the ideals that he and his Bull Moose Party enunciated in 1912 would resonate in American political life for decades. They still do. They shaped much of Franklin Roosevelt's New Deal and influenced domestic policy until the 1980s, when the Reagan Revolution began dismantling social programs. Even now, echoes of that campaign can be heard in debates on what government should do for citizens and how to make it more accountable.

Roosevelt's odds of unhorsing an incumbent President were long, but not as long as they would have been in previous election years, when nominees were chosen by a handful of bosses and rubber-stamped at state party caucuses. In 1912 a dozen states were letting voters do the choosing in primaries, a political innovation just beginning to catch on. If T.R. could win big in the primaries, he could present himself as the people's choice and Taft as the creature of the bosses.

Collectively, the primaries gave T.R. a shot at 362 votes, and he stunned the party by walking off with 278 of them. Taft finished a distant second, with 48. But in the 36 states without primaries, Roosevelt was outflanked by the bosses. In June, as delegates headed to Chicago for the national convention, Taft's men boasted that their candidate had 557 votes--17 more than he needed for the nomination. T.R. could see that his primary delegates plus delegates from renegade factions elsewhere had left him about 70 votes short. His aides noisily challenged the legitimacy of scores of Taft supporters, but when it became clear that he could not win, T.R. executed one of the gutsiest maneuvers in the annals of American presidential campaigns: he denounced the Republicans as thieves and bolted the convention.

A bolt spared Roosevelt the humiliation of losing to Taft. It also kept his candidacy alive on a brand-new ticket of his own creation, the National Progressive Party, better known as the Bull Moose Party, a nickname that came from the answer T.R. had given when someone in a crowd yelled out to ask how he felt. "Like a bull moose," he yelled back.

The Bull Moose Party got off to a thundering start. Within seven weeks, the Progressives had established the party in nearly every state and were back in Chicago for their first national convention. But who were the Progressives? Although Republicans of the day cast the Progressives as radicals, in truth they were teachers and lawyers, farmers and small-town folk, urban reformers of every ilk, crusaders for peace and women's suffrage, champions of the little guy. They were less a movement than a catch basin for civic-minded men and women impatient with politics as usual but a bit frightened of Eugene V. Debs and his Socialist Party. While many Progressives could not see past their pet causes, T.R. managed to bring them together in a big tent held aloft by the idea that the government, which ought to serve the people, had been hijacked by special interests. "To destroy this invisible government, to dissolve the unholy alliance between corrupt business and corrupt politics is the first task of the statesmanship of the day," the Progressive platform declared.

A brief for a strong Federal Government, the Progressive platform was so far ahead of its time on many points (Social Security and the minimum wage, for example) that it would take a generation and another Roosevelt, T.R.'s fifth cousin Franklin, to bring them into being. In hopes of protecting the investing public from swindlers, the Progressives called for federal regulation of stock offerings and fuller disclosure of corporate financial transactions, ideas that found their way into the creation of the Securities and Exchange Commission in 1934....