HANOVER, New Hampshire — Joe Biden derided the healthcare proposals of his 2020 Democratic primary opponents while also taking aim at President Trump for trying to gut his former boss's signature healthcare law.

"The future of healthcare one of the biggest issues in this election," the former vice president and Delaware senator said Friday, speaking to an audience of about 400 people during a town hall at Dartmouth College.

Biden has since rolled out his healthcare proposal called the Medicare for All Act, which would gut private health insurance, as an attack on his former boss's signature healthcare achievement, and he reiterated that argument on Friday. Some of his opponents, he said, "want to get rid of Obamacare and start again with something new."

"I'm not for that," he said.

The rhetoric against Democratic rivals, including Sens. Kamala Harris of California and Bernie Sanders of Vermont, has been similar to what Trump has used about the Medicare for All Act. But Biden also took several shots throughout his speech at Trump, whose administration has signed onto a lawsuit asking the courts to invalidate Obamacare.

"That ain't right!" a member of the audience shouted after Biden brought attention to the lawsuit.

Biden's healthcare plan would expand Obamacare and introduce a government plan similar to Medicare that people would be allowed to buy into. The former vice president added to his pledges, promising to provide free tuition to medical school students who go on to work in rural areas and to end the HIV epidemic by 2025.

Obamacare extended health insurance to more than 20 million people by expanding the government's Medicaid program to the poor and by subsidizing private health insurance for people who don't get coverage through a job. The subsidies, however, only extend to people if they make under 400% of the federal poverty level, or about $48,560 a year for an individual and $100,400 for a family of four. The rest have to pay full price, which has resulted in millions of people being priced out and left either without coverage or with coverage that doesn't cover preexisting illnesses.

The Biden plan acknowledges the affordability issue would upend the Obamacare formula so that people would pay no more than 8.5% of their income on health insurance.