Former President Barack Obama on Wednesday warned that Republican-backed efforts to undo the Affordable Care Act would cause “real human suffering” and said “people are alive today" because of his signature legislation.

“So when I see people trying to undo that hard-won progress for the 50th or 60th time, with bills that would raise costs or reduce coverage or roll back protections for older Americans or people with pre-existing conditions, the expecting mom or the child with autism or asthma for whom coverage would once again be almost unattainable, it is aggravating,” Obama said at an event hosted by the Bill & Melinda Gates Foundation in New York City.

“And all of this being done without any demonstrable economic or actuarial or plain common-sense rationale. It frustrates. And it’s certainly frustrating to have to mobilize every couple of months to keep our leaders from inflicting real human suffering on our constituents,” the former president continued.

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Senate Republicans are making another attempt to repeal the Affordable Care Act, Obama’s landmark legislation, after narrowly failing to do so in August. However, lawmakers have yet to rally around the latest plan pushed by GOP Sens. Lindsey Graham and Bill Cassidy.

House Republicans voted to amend or repeal the Affordable Care Act more than 60 times while Obama was in office. President Donald Trump has pushed Congress to make another go this month at repealing Obamacare, an oft-repeated campaign promise that helped get Trump and congressional Republicans elected in 2016.

Despite Obama's warnings about health care, his speech to the group, which is focused on global development, was mostly optimistic.

“People are alive today because of [Obamacare], and that's progress,” he said.

Obama has weighed in on political debates only sparingly since leaving office. The health care battle, immigration and the race-fueled riots in Virginia are among the few issues he has spoken out on publicly since Trump took office.

The former president on Wednesday warned that the "rise of nationalism and xenophobia" cannot cause generations to think the world has regressed. The themes were similar to the tone he took during his farewell speech in January, when he called on young people and those unhappy with the current political environment to get involved.

“We just have to reject the notion that we’re suddenly gripped by forces that we can’t control and embrace the longer, more optimistic view of history and the part that we play in it,” Obama said.