In 1971, a young Naval lieutenant named John Kerry pleaded with the Senate Foreign Relations Committee to stop a war. Four decades later, Kerry will return to that same committee table, this time as Secretary of State, to advocate for U.S. military action in Syria.

Kerry will be joined Tuesday by Secretary of Defense Chuck Hagel–the two men both military veterans who served for years together on the senate panel that will hold hearings on Syria and President Obama’s quest for Congressional approval of military action there. The chairman of the joint chiefs, Gen. Martin Dempsey will also testify. Kerry will testify before the House Foreign Affairs committee Wednesday.

Tuesday’s testimony will be a significant marker in a career that began for Kerry in that same Senate room 42 years ago. Kerry became a national figure at age 27 when he testified in uniform before the committee. He seemed to captured the national sentiment of a country growing weary with the Vietnam War when he asked senators: “How do you ask a man to be the last man to die for a mistake?” Kerry was awarded the Silver Star, the Bronze Star, and three Purple Hearts for his service.

Recalling those formative experiences in Vietnam, a much older Kerry noted in remarks last week that his country is tired of war. Yet he has quickly emerged an outspoken advocate of a hard-line approach against Syrian President Bashar al-Assad. The U.S. government has said it has evidence that indisputably shows the Assad regime ordered chemical attacks against civilians in a Damascus suburb on Aug. 21, killing more than 1,400, including hundreds of children.

During his confirmation hearing in January, Kerry commented on how the world had changed from the Vietnam War era to the current fight against terrorism.

“Nearly 42 years ago, Chairman Fulbright first gave me the opportunity to testify before this committee during a difficult and divided time for our country,” Kerry said. “Today I can’t help but recognize that the world itself then was in many ways simpler, divided as it was along bi-polar, Cold War antagonism. Today’s world is more complicated than anything we have experienced.”

In two speeches last week, Kerry called the chemical attack “a moral obscenity,” and “a crime against humanity.” He told a war-weary nation, and a skeptical world arena, that “fatigue does not absolve us of our responsibility.”

Then on Saturday, Obama said he would seek congressional approval before launching a military campaign in Syria that he described as limited in scope and duration.

Asked what direction the president would take if Congress fails to authorize military action, Kerry said on NBC’s Meet the Press Sunday, “I do not believe the Congress of the United States will turn its back on this moment.”

“The challenge of Iran, the challenges of the region, the challenge of standing up for and standing beside our ally, Israel, helping to shore up Jordan—all of these things are very, very powerful interests and I believe Congress will pass it.”

The White House sent Congress a draft resolution and officials quickly called for an unclassified meeting with members of Congress as part of a “flood the zone,” strategy to gain support. But Democratic Senator Patrick Leahy of Vermont, the chair of the Senate Judiciary Committee, said that lawmakers would amend the administration’s draft proposal for the action, saying that it is currently too broad in scope.

Republican Sens. John McCain of Arizona and Lindsey Graham of South Carolina—both outspoken advocates for tougher military measures against Syria—met with Obama at the White House over Labor Day. The two senators have faulted Obama’s proposal as too little, too late, and have urged him to intervene further on the side of the rebels.

“We cannot in good conscience support isolated military strikes in Syria that are not part of an overall strategy that can change the momentum on the battlefield, achieve the president’s stated goal of Assad’s removal from power, and bring an end to this conflict, which is a growing threat to our national security interests,” McCain and Graham said in a joint statement.

If Obama is able to gain their support, the resolution to authorize military action in Syria would stand a greater chance of passage in the Senate.

Kerry worked much of Labor Day to persuade fellow Democrats to vote with the president. In a Monday conference call, Kerry reportedly told House Democrats that they face a “Munich moment” as they weigh whether to approve striking Syria, two sources with knowledge of the call told NBC News.

Kerry was referencing the 1938 Munich Pact which ceded control of part of Czechoslovakia to Nazi Germany—a moment that history has harshly judged as an appeasement of Adolf Hitler that strengthened him ahead of World War II.