With his signature achievement on life support, former President Obama weighed in on the debate over a replacement for ObamaCare, invoking John F. Kennedy and saying it will take "courage" to craft a law that protects society's most vulnerable.

Obama spoke at the John F. Kennedy Presidential Library and Museum in Boston, days after House Republicans shredded his controversial health care plan. While he did not criticize Republicans or attack President Trump in his 30-minute speech, defending the law was clearly foremost on his mind.

“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 … but it does require some courage to champion the vulnerable and the sick and the infirm and those who often have no access to the corridors of power,” said Obama, who received the Profile in Courage Award from the Kennedy family.

“I hope they understand that courage means not simply doing what is politically expedient, but doing what they believe deep in their hearts is right,” he added.

According to The Hill, Obama asserted that the debate over health care in the U.S. “is not settled.”

The former president focused much of his address on the legacy of President Kennedy, as the library prepared to mark the 100th anniversary of his birth later this month. Obama noted the Kennedys had long advocated for health care reform, and in particular, the late Sen. Edward Kennedy.

Rep. Joe Kennedy III, D-Mass., said Obama earned the award by meeting many challenges that faced him during his presidency.

"It's about understanding the challenges we face as a country and as a planet and mustering the political will to do what is right even if what is right at that moment isn't necessarily popular," Kennedy said.

Meanwhile, Republicans' American Health Care Act faces an uncertain future as it heads to the Senate.

Trump urged Senate Republicans to “not let the American people down” as the debate shifts.

Some senators have already voiced their displeasure with the health care bill that cleared the House last week. They cite concerns about potential higher costs for older people and those with pre-existing conditions, along with cuts to Medicaid.

A moderate Republican, Sen. Susan Collins of Maine, said the Senate will not take up the House bill and will instead start from scratch.

Trump's budget director, Mick Mulvaney, also said the version that gets to the president will likely differ from the House measure. Such a scenario would force the House and Senate to work together to forge a compromise bill.

The Associated Press contributed to this report.

Ryan Gaydos is a news editor for Fox News. Follow him on Twitter @RyanGaydos.