The dome of the Capitol under constructionon May 9, 1861. (Library of Congress Prints and Photographs Division)

If the persistent griping and gridlock on Capitol Hill in recent years has produced a do-nothing Congress, by contrast the 37th — which served from 1861 to 1863 — was the do-everything counterpoint.

It took monumental steps in accelerating the end of slavery. It helped to modernize the nation’s tax and banking system. It created the U.S. Department of Agriculture. It opened vast swaths of the country to development and expansion by creating the first transcontinental railroad and handing over huge amounts of public land to create colleges and serve as settlements for citizens.

“It was the members of this Congress — sometimes by accident and sometimes by design — who drew the blueprint for a new America,” historian Leonard P. Curry wrote of the 37th.

Why did it happen? How did it happen?

The simple answer: secession.

The tide of war begins to turn in favor of the Union

By the summer of 1861, nearly a third of the desks in both houses of Congress sat empty, vacated by members who had departed Washington for the Confederacy, leaving a splintered Democratic Party and a huge Republican majority with a Republican president willing to sign sweeping legislation. Ideas that had been mired for years or even decades in partisan gridlock finally could become reality.

“The people left behind said, ‘This is our golden opportunity,’ ” said U.S. Senate historian Donald Ritchie. “It opened the floodgates.”

What came through those floodgates were measures of such breadth and significance that they continue to shape American life.

One of the early landmark bills was the Revenue Act of 1861. Designed to help fund the Union war effort, it instituted the first federal income tax. That measure, along with the National Banking Act passed later in the session to create a national currency, laid some of the country’s key economic foundations.

By April 1862, lawmakers saw fit to use their authority to end slavery in the District of Columbia, a move that paved the way for President Abraham Lincoln’s Emancipation Proclamation the following year and eventually for the abolition of slavery.

The following month, Congress created the Department of Agriculture, which would help fuel the nation’s agrarian growth in the wake of war. Lincoln called it “the people’s department.”

About the same time came the Homestead Act, which allowed anyone older than 21 who had never taken up arms against the U.S. government to apply for 160 acres of land to call his own.

Noted author Stephen W. Sears of Landscape Turned Red and Civil War buff Gene Thorp square off over Gen. George B. McClellan’s place in history.

A million Americans did just that, and the result was the nation’s rapid westward expansion.

That same frontier spirit lay behind the Pacific Railway Act of 1862, which authorized the construction of the first transcontinental railroad. It also involved granting millions of acres of public land to railroad companies building the project, which led to the development of new towns along the route.

In the summer of 1862, Congress passed the Morrill Act, also known as the Land Grant College Act, which granted each state 30,000 acres per congressional seat. Funds from the sale of those lands were used to establish new universities and enhance existing ones. Scores of major colleges throughout the country, from Cornell to Clemson to Texas A&M, grew out of that effort.

Such legislation spoke in part to a practical reality — the federal government was spending nearly all its money on the war, but it had plenty of land to give away. But it also spoke to a philosophy among many members, at least in the majority, that the nation should leverage the resources it had for growth and expansion.

“They were thinking about rebuilding the nation,” Ritchie said. “They thought they were going to win this war, and they were thinking about what kind of country was going to emerge from the war. They were shaping the future.”

The mood was far from upbeat inside the Senate chamber on July 4, 1861, as the presiding officer gaveled the 37th Congress into session. The Rev. Byron Sunderland offered up a solemn Independence Day prayer.

“Almighty and everlasting God, be not angry with us for our sins,” he began, adding, “Disasters have befallen us and darkness broods in the land. And now we ask Thy mercy as the Senate is convening at a most momentous crisis of our history. Give to Thy servants all needed help. Add to their deliberations wisdom and unanimity.”

Not that anyone needed reminding about the gravity of the situation. Aside from the empty seats, whose former occupants were now antagonists, the Capitol dome remained under construction, its future uncertain — not unlike the country itself.

Lincoln had summoned Congress for an extraordinary session that summer, urging lawmakers to give him “the legal means for making this contest a short and a decisive one.”

They granted the new president his war powers, though the fighting to follow proved anything but short and decisive.

For the men in the Senate chamber that day, as well as for their counterparts in the House, the war itself was inescapable and ­ever-present throughout their tenure, demanding constant attention.

But even as soldiers began drilling on the Capitol lawn and the sounds of distant cannon fire rumbled across the Mall, the conflict remained far from their only focus. They steadily racked up an impressive list of achievements.

“It’s a long list, astonishingly long,” Princeton University historian James M. McPherson, author of the Pulitzer Prize-winning book “Battle Cry of Freedom,” said of the accomplishments of the 37th Congress. “That legislation had an impact that went on for decades and generations.”

McPherson said the men on Capitol Hill knew well the monumental tasks they were undertaking — hence the heated, often-vitriolic debates.

“The Congress was well aware of the historic consequences of what they were doing,” McPherson said. “It was a sense of great challenge but also great opportunity. It created a sense of excitement, but also probably apprehension.”

Ritchie, the Senate historian, ranks the 37th Congress as among the most productive ever, on par with the very first Congress, which helped cobble together a nation; the “New Deal” Congress of 1933 and the “Great Society” Congress of 1965.

“These were Congresses that were just extraordinary in terms of passing lots of legislation,” he said.

Even so, the initial reviews of the 37th were, at best, mixed.

“It is an historic body, and has done its duty ably and fearlessly,” one Midwestern newspaper declared, according to Curry’s book, “Blueprint for Modern America.”

And Adam Gurowski, an influential Polish-born writer who spent the war years in Washington, proclaimed that the 37th Congress had “inaugurated and directed a new evolution in the onward progress of mankind.”

But the Philadelphia Inquirer labeled the 37th a “congregation of incompetents” and said its members had shown themselves to be “without the intellect to realize the true condition of this country, and utterly without the legislative ability to provide for it if they did.”

Perhaps the more common sentiment among the members themselves was a lingering uncertainty about how the decisions they had made would pan out, coupled with hopefulness that they had been the right ones for the country.

As the 37th Congress wound to a close in 1863 — now working under a Capitol dome well on its way to completion — Ohio Republican Sen. John Sherman predicted that the landmark laws passed during its two years “will be a monument to good or evil. They cover such vast sums, delegate and regulate such vast powers, and are so far-reaching in their effects, that generations will be affected well or ill by them.”

After the final debates had ended and the last vote had been counted, Republican Senate Leader William P. Fessenden reflected on all that had happened to change the course of the America that would emerge from the war.

“With all the labor and anxiety it has cost me, I am gratified to reflect that we have accomplished much,” he observed. “With all its faults and errors, this has been a great and self-sacrificing Congress. . . . Future times will comprehend our motives and all we have done and suffered.”