We know who started the United States. George Washington, Thomas Jefferson, Ben Franklin — these are the statesmen we learn about in school and who fought and won wars and started the post office. Alexander Hamilton, perpetually a Founding Father also-ran, has gotten a bit of a boost in recent years, what with the Pulitzer Prize-winning musical and all.

And we know who was involved in the American Civil War — Abraham Lincoln, Jefferson Davis. Ulysses S. Grant, Robert E. Lee. Even devout abolitionist Thaddeus Stevens is a little better-known these days, what with that Oscar-winning movie “Lincoln” and all.

But there is a period in American history that is considerably less famous to the general public: the time between just before the War of 1812 until about 1852, when the wheels start to come off the Union.

This is the period covered by University of Texas historian H.W. Brands in the new book “Heirs of the Founders: The Epic Rivalry of Henry Clay, John Calhoun and Daniel Webster, the Second Generation of American Giants.”

“You go to any bookstore and look at the section on American history,” Brands says. “There's a huge number of books on revolution and a whole bunch even more on the Civil War, and it really drops off dramatically in between. There was a gap to be filled there.”

Brands became interested in the story of how the founders handed off the republic to the next generation. Brands focused on the so-called Great Triumvirate of second-generation American statesmen who all lived and died in comparative lockstep: Henry Clay, John Calhoun and Daniel Webster.

To make a complicated story extremely short, Clay (1777–1852) was House speaker, served as John Quincy Adams’ secretary of state and successfully proposed the Missouri Compromise, which gave us Missouri as a slave state and Maine as a free state.

Webster (1782–1852) was, broadly speaking, the sexiest of the trio: a gambler who was constantly in debt, a senator, a secretary of state and a legitimately brilliant orator who once made an argument before the Supreme Court that made Chief Justice John Marshall cry. (Webster also spoke for four hours, so maybe he was brilliant, or maybe Marshall was just glad he stopped.)

The reputation of South Carolinian Calhoun (1782–1850) has probably suffered the most in the years since his death, and understandably so. Vice president to both Adams and Andrew Jackson, Calhoun went all-in on slavery, once calling it “a positive good, an ornament of the South’s superior culture.”

The trick to understanding this time period and these three men, Brands argues, is to understand that they (especially Clay and Webster) saw American democracy as fragile and dependent on the spirit of compromise, on the idea that my opponent is not my enemy, if it were going to succeed in the long term. The republic’s ability to “muddle through,” as Brands says, is a feature, not a bug.

Brands says Clay understood this the best.

“Henry Clay was probably the most gifted politician in his generation,” Brands says.

Clay was, by contemporary standards, a man of mixed morality. “Clay was a slaveholder who worked to end the institution of slavery,” Brands says. “He thought slavery was bad for the country, bad for the slaves and bad for the slave-holders. But he wasn’t an abolitionist. He knew the question was complicated, and he also understood that he would have more credibility with the other slaveholders if he held onto his slaves and made the case against slavery as a slaveholder.”

Clay believed that the Southern economy would outgrow slavery just as the Northern economy had.

“Clay believed in the self-correcting tendency in democracy,” Brands says, “and you can see that in his compromises. He didn't think they ended debate over these subjects, but if he could buy 10 or 20 or 30 years, then things would change.”

This did not happen.

Brands doesn’t disagree than Calhoun’s historical reputation is deserved, especially given his explicitly pro-slavery views starting in the 1830s

“He was probably the most intellectually adept of the three,” Brands says. “Calhoun was probably the best lawyer of his generation in terms of having an analytical mind, which could devise an argument in favor of whatever position he needed to defend, so he erected a very elaborate superstructure around the idea that the Constitution was this compact between states. Had he been from Massachusetts, he would have worked just as hard on the opposite side.

"He was somebody who would follow his intellect to however far the intellect would take him and never stopped to question the moral weight of the argument.”

What you end up having in “Heirs” is a situation in which alliances shift given the interests of the regions these men represent. Clay and Calhoun are advocates of federal power, with Webster arguing during the War of 1812 that New England is within its rights to secede from the Union.

“Over the next 15 years," Brands says, "the alliances switch. It becomes Webster and Clay against Calhoun regarding states' rights and slavery," even as Webster (to the dismay of many Northerners) endorsed the strengthening of the Fugitive Slave Act as a Union-saving measure. It was, by any measure, an enormously complicated time.

The more one looks at the time period covered by “Heirs,” the more relevant it feels. Inequality, regional interests, state versus federal law enforcement, tariffs — it's all there.

“Democracy is founded on the principle that all men are created equal,” Brands says. “Then, the greatest inequality was slavery. Now, we are dealing with income inequality, gender and sex inequalities, racial inequalities. So the question of how much inequality can American democracy stand seems to be getting sharper over the last 20 or 30 years.”

The relationship between federal and state law has taken on all-new complexities, from marijuana legalization on the state level to the notion of sanctuary cities.

“The spirit of compromise that this middle generation excelled in died with it,” Brands says. “The next generation had no interest in compromise. Within 10 years the nation was locked up in a civil war.”