In the name of presidential ambition, is anything off-limits? If the recent primary season is any indication, the answer is a disheartening no.

Both entertainment and embarrassment, the tweets, accusations, proclamations and insults revealed a level of bad craziness that just might make Hunter S. Thompson envious. Little wonder if we dread the slugfest between Donald Trump and Hillary Clinton, opening rounds last week in Cleveland and this week in Philadelphia. The next three months promise to be brutal.

But before we bid adieu to the 11-month spectacle, we can turn to Geoffrey Cowan’s account of the country’s first primary season, 1912, a year of possibly greater discontent.

Like most assured historians, Cowan reminds us that those who forget the past are condemned to repeat it, and from recent events, it would seem we have forgotten everything.

No musty account of top-coated and mustachioed politicians, “Let the People Rule: Theodore Roosevelt and the Birth of the Presidential Primary” is a lively, relevant primer in the sausage-making of candidate selection.

While the story doesn’t have the lavish detail or scope of, say, Edmund Morris’ “Colonel Roosevelt,” Cowan, president of the Annenberg Retreat at Sunnylands and a professor at University of Southern California, isn’t interested in biography.

Instead, he’s after the origin of the primary system: how Roosevelt steered the political process in this country away from the decisions of men in back rooms to the will of the people.

Along the way, however, his story takes a surprising turn that challenges Roosevelt’s place in our presidential pantheon. No reputation is ever beyond reproach (witness Cowan’s incriminating assessment of the bribery charges against the famed defense attorney in his 1993 book, “The People v. Clarence Darrow”).

William Howard Taft had been Roosevelt’s protege, a hand-picked successor to the famous Rough Rider who in 1908 bowed out of American politics. Even though the men had vastly different styles – if Roosevelt was Trump, then Taft was Jeb – they managed to see eye to eye.

But during the years of the Taft presidency, Roosevelt could see his legacy being rewritten by conservatives and “stand-patters,” congressional leaders who preferred inaction to reform, and in 1912, he decided to stage a comeback.

Only Taft stood in his way. Backed by party bosses, federal officeholders and political cronies – all delegates to the June convention in Chicago – Taft was favored as the Republican nominee. Breaking that chokehold required articulating a more radical vision.

“We believe that unless representative government does absolutely represent the people it is not representative government at all,” Roosevelt told his supporters in Ohio, a sentiment that would soon lead to him endorsing a new system of selecting delegates: not from the party machinery but from the voters in each state.

Roosevelt’s gambit was a hard sell (not every state adopted it). It divided the Republican Party and represented a radical position for those, including Roosevelt, who believed that “only certain people are fit for democracy,” a reference dismissing the “Negro majority” in the South. Cowan makes clear it’s naïve to think that high-mindedness trumps ambition in politics.

There is Democracy, and there is democracy. If the former is ideal – a government of the people, by the people and for the people – then the latter is the messy, imperfect methods we have tried in 240 years to attain that goal, and in 1912 the stakes were especially high.

A decade into the new century, America had been whipsawed by a series of recessions. The abuses of the Gilded Age still rankled the citizenry who experienced as great a divide between rich and poor as had been seen. Labor unions fought for a place at the table, and some sought to rein in the influence corporations had on politics.

Then as now, populism seemed the best solution, and Roosevelt played it to his advantage, pacing the stage, tossing pages of his speech to the floor, even evoking Robespierre in one speech. Reporting on such a performance, the Nation magazine described “his violence of language, his recklessness of assertion, his apparent inability to reason coherently, make of him a spectacle disturbing to his friends and mortifying to the country” and concluded that “there appears the almost insane hatred of Mr. Taft.”

The frenzy polarized the party, and the convention in Chicago was anarchic. Thirteen states had held primaries, and after winning nine of those contests, Roosevelt and his followers felt entitled to the nomination. But the party leadership didn’t agree and defended its position by stringing barbed wire around the rostrum and enlisting guards and police for security.

When the dust settled, Taft had won the nomination, and Roosevelt, too proud to concede, formed the Progressive Party. But Cowan shows its promise was short-lived.

In courting the Southern white vote Roosevelt’s Progressives prohibited the Southern black delegates, who had left the GOP, from joining the new party.

Few historians have given this shameful chapter in the Progressive Party the attention it deserves, and Cowan’s documentation, drawn mostly from newspaper accounts from summer 1912, is compelling.

Roosevelt wrote, “I earnestly believe that by appealing to the best white men in the South, and by frankly putting the movement in their hands from the outset, we shall create a situation by which the colored men of the South will ultimately get justice.”

In the end, the theatrics and racism didn’t win the election. By splitting the vote, Roosevelt and Taft allowed Woodrow Wilson to beat the GOP in every state in the South and take the White House. Ironically, Wilson’s administration introduced a flood of discriminatory legislation.

“Let the People Rule” is a bracing reminder that we’re not above such tactics today. Congressional districts get realigned. New voting laws are written, and the intelligence of the electorate is questioned.

If the battle between Roosevelt and Taft had a rancor, vitriol, a passionate intensity that sounds familiar, then we would be wise to realize that in a contest where the ends justify the means, what a candidate represents is not who the candidate is. Roosevelt acted, as Cowan concludes, “like many and most politicians: doing everything necessary to win.”

Credit the strength of the republic that it doesn’t always work out.