Mayor Bill de Blasio is making a big push to get more New Yorkers health insurance. It's his way of trying to save Obamacare from being repealed when President-elect Donald Trump takes office. Our Grace Rauh has the story.

Obamacare is in jeopardy.

"From the beginning I said it wasn't going to work and it didn't work," President-elect Donald Trump said on the campaign trail in October.

President-elect Donald Trump says that within his first 100 days in the White House he will repeal and replace President Obama's signature health care initiative, the Affordable Care Act. The promise is prompting Mayor de Blasio to take action. He says he wants to sign-up 50,000 New Yorkers for health insurance over the next year.

The aggressive $8 million outreach effort by City Hall, which includes door-knocking and calling the uninsured, is the latest front in the mayor's battle against the future president. Since Trump's victory, de Blasio has transformed not just into a vocal critic of Trump's — but one willing and able to use the biggest city in the country to drive his message home.

"There's no choice but to fight here," the mayor said. "What's the alternative? To let our people have their insurance taken away from them? 1.6 million people robbed of their health insurance. We would never accept that."

As far as de Blasio is concerned, insuring more Americans may be a way to keep Obamacare from disappearing under President Trump.

"This going to get real complicated real quick for the Republicans," de Blasio said. "And we want to make it more complicated by increasing the number of people who are signed up."

Signing up more New Yorkers for health insurance is also good for the city's bottom line. Officials estimate that the city's public hospital system could save $40 million.

Trump has signaled an openness to keeping parts of Obamacare, like the requirement that people with pre-existing conditions be covered and the provision that allows children to remain on their parents' insurance into their mid-20s. It is not clear how he could repeal the rest of the law and keep the most popular parts of it.