Former President Obama has ventured back into the political debate for the first time since he left office. In Boston Sunday night, he received the John F. Kennedy Profile in Courage Award, which is given annually by the Kennedy family to recognize commitment to public service.

The Kennedy family honored Obama for a number of his policies, including restoring diplomatic ties to Cuba; fighting climate change; working to reduce the risk of nuclear war; and for his signature legislative accomplishment, the Affordable Care Act, which President Trump and House Republicans are trying hard to dismantle.

Calling For 'Courage To Champion The Vulnerable'

This was Obama's third public event since he left the White House — and the first in which he directly challenged Republicans. As he accepted the award, Obama said many of the lawmakers who voted for the Affordable Care Act in 2009 exemplified the kind of courage for which the award is named.

“These freshmen congressmen and women knew that they had to make a choice: that they had a chance to insure millions; and prevent untold worrying and suffering and bankruptcy — and even death," he said. "But that this same vote would likely cost them their new seats.”

And Obama noted, many did lose their seats because, he said, they put the welfare of the country above their own political survival. And he urged current members of Congress to “look at the facts and speak the truth” — even when it contradicts their party’s position.

“I hope that current members of Congress recall that it actually doesn’t take a lot of courage to aid those who are already powerful, already comfortable, already influential," he said. "But it does require some courage to champion the vulnerable, and the sick, and the infirm.”

In addition to political courage, Obama also praised what he called "the ordinary courage of everyday people." And while he never referred to President Trump by name, references to his policies were hard to miss, especially when he talked about the courage of the so-called DREAMers, or young immigrants brought to the U.S. by their parents and residing with some granted protections against deportation.

"Who suppress their fears to keep working and striving in the only country they've ever called home — and every American who stands up for immigrants because they know that they're parents or grandparents or great-grandparents were immigrants too, and they know that America is an idea that only grows stronger with each new person who adopts our common creed," Obama said.

Obama addressed an appreciative blue state crowd of Kennedy family members, Massachusetts politicians and business leaders, as well as former Vice President Joe Biden and former Secretary of State John Kerry. And while Obama resisted naming Trump, many at the event couldn't resist pointing out the contrast between past and present presidents.

"May I say what a delight it is and an honor — and frankly, a great relief to be in the presence of the Obamas again," singer James Taylor said, drawing laughs and applause from the crowd.

Former President Obama listens to musician James Taylor during the ceremonies. (Steven Senne/AP)

And others were more willing to name the current president.

"Barack Obama was able to pass the Affordable Care Act as a continuation of the vision of President Kennedy and Ted Kennedy," said Sen. Ed Markey, who spoke to reporters about the Republican effort to repeal Obamacare. "Today Donald Trump is trying to destroy that vision, and we are going to make sure that President Kennedy and President Obama's vision stays on the books as the law in our country."

That's proving to be a tough fight for Democrats with Republicans in control of the White House and Congress.

But Sunday night in Boston belonged to the former president, who received this year's award three weeks before the 100th anniversary of President Kennedy’s birth. Obama called it an honor that reminds him that even out of office, he'll do all he can to advance the spirit of service that John F. Kennedy represents.