Fresh off his Supreme Court victory on Obamacare, President Obama on Wednesday met with supporters of the law in Nashville, Tennessee, to say the government needs to do even more to sign people up for health insurance.

"There are huge areas of improvement and, frankly, there's still a lot of people who aren't insured," Obama said. "Part of the design of the Affordable Care Act was that some people were going to buy health care on the marketplace; in some cases, we were going to allow states to expand their coverage through individualized programs in their states."

"I think because of politics, not all states have taken advantage of the options that are out there," he said. "Our hope is, is that more of them do."

Obama said about a third of the people who were uninsured before Obamacare became law have signed up, but he said, "We still have to sign a bunch of people up."

To stress his point, the presidential motorcade stopped at Kelly Bryant's house to take her with him to Stratton Elementary School, where he was heading to participate in a discussion on the Affordable Care Act. Bryant had written to him in January to thank him for health-care reform.

"It turned out it she was so close to the school, we said 'we may as well just swing by and get her,'" Obama joked about the untraditional stop.

"In 2011, I was diagnosed with breast cancer," Bryant wrote in her letter that ultimately landed her on the same stage as Obama. "This past year, I decided to make a career shift …That is where health-care reform came to play for me…I was able to find high quality, affordable insurance when I needed it the most. Every month when I pay my premium, I am not angry or stressed. I am thankful that it is there for me and continues to be."

"I am living proof of a president who listens and cares about the American people," Bryant said as she introduced Obama, who spoke and took questions for more than an hour.

According to the White House, the audience of about 150 included numerous locals who had written to Obama about the ACA. Also in attendance was Natoma Canfield of Ohio, whose letter about losing her health-care insurance, written five and a half years ago now hangs in the White House.

"I would always refer back to her letter whenever things got a little bleak and Congress wasn't behaving as sensibly as Jim Cooper behaves," Obama said of the letter, referring to the Tennessee Democrat. Canfield traveled to Nashville with Obama aboard Air Force One.

"Not only are 16 million people getting health insurance who didn't have it before … it's actually ended up costing less than people expected," Obama said of the law.