If Congress got what it deserved, the Capitol dome would never have been permitted to be the backdrop for Tuesday’s Concert for Valor, which marked Veterans Day.

Why? The 535 lawmakers who work there have cravenly dodged their constitutional responsibility to make the tough decision about whether President Barack Obama is right to lead the country into war against the Islamic State in Iraq and Syria.

What a contrast with the courage of the men and women in uniform justly celebrated on the Mall. They were willing to face death for their country. Capitol politicians won’t risk political inconvenience.

Senators as politically different as Tim Kaine, D-Va., and Rand Paul, R-Ky., agree that Obama is launching airstrikes and other offensive military operations in the Middle East without proper legal authority. Many constitutional scholars share that view.

But Congress didn’t want to vote on the matter before the midterm elections, so it took a pass.

Kaine calls Congress’s position “the height of public immorality.” His vocal disagreement with Obama and other Democrats on the issue has been especially noteworthy, given his usual support of the president.

“What could you do that would be more publicly immoral than ordering people to risk their lives without having a discussion about whether the mission is worth it or not?” Kaine said Wednesday at a forum at the Wilson Center.

Many in the crowd on the Mall had a similar view. They voiced gratitude for the veterans but contempt for the politicians who had sent them to fight.

“It’s definitely cowardly — them not bringing it to a vote before the elections,” said Frank, 29, a veteran who served in Afghanistan and now lives in Southern Maryland. He declined to give his surname because he’s still in the Army Reserve.

“The American people have a right to know how their tax dollars are being spent,” he said.

Obama is to blame, too, of course. Although he said from the start that he’d welcome congressional support, he hasn’t bothered to send Congress a draft bill that would authorize his military actions.

“To keep everything fair and equal, (Obama) should get congressional approval,” said Jo Miller, 24, of Seaford, Del. That’s necessary, she said, because “we’re not directly threatened” in Iraq.

The Wilson Center forum offered some eye-opening details about how Congress’s AWOL status has permitted the White House and Pentagon to wage war in numerous countries with little or no oversight. The event was designed to pressure Congress to take up its responsibilities as it returned from its lame-duck session.

Harvard Law professor Jack Goldsmith, a former special counsel to the Defense Department, said that when he testified before Congress last year, he was stunned by key senators’ lack of knowledge about U.S. military operations, such as drone strikes in Yemen, Somalia and Pakistan.

“It was remarkable how little the members of the Senate Armed Services Committee knew about where we were fighting and against whom,” Goldsmith said. “They don’t even know where it’s going on.”

Nobody doubts that Congress would approve military strikes against the Islamic State, if it ever got around to discussing the matter. Most lawmakers want to quash a potential terrorist haven in the heart of the Middle East just as much as Obama and the Pentagon do.

But an actual debate on the issue would require taking a stance on pesky details, such as: How long would the operation last? Do we rule out ground troops? How are we going to pay for it?

Congress as a whole prefers to avoid such potentially hazardous questions. It’s easier to let Obama take the heat.

Kaine, to his credit, is an exception. Driven in part by concern for Virginia’s large military population and respect for the state’s leading role in crafting the Constitution, Kaine has become one of Congress’s most prominent advocates for reforming the rules on waging war.

He hasn’t hesitated to fault Obama, even though he was one of the president’s earliest supporters in the 2008 campaign. Kaine said it was “ridiculous” for Obama to rely on congressional authorizations from 2001 and 2002 to justify war against the Islamic State today.

“I only have one obsession, and this is it,” Kaine said.

It’s a good way to honor veterans, both past and future.

Robert McCartney writes a column about local issues in The Washington Post’s Metro section.