The Democratic senator from Wisconsin was at the Children's Hospital of Wisconsin today with Senator Susan Collins, a Republican from Maine.
They announced the signing of the ADAM Act into law.
It's named for 17-year-old Adam Lemel, who died on the basketball court during a high school game in 1999.
His death was attributed to an undetected heart condition, and it's hoped that external defibrillators could save the lives of others like him.
The act sets up a national resource center for schools to access training and fund-raising for the defibrillators.