Last week in Florida, at the University of Tampa, President Joe Biden promised to protect and strengthen Social Security and Medicare, as well as lower health care costs. Mandel Ngan/AFP via Getty Images hide caption toggle caption Mandel Ngan/AFP via Getty Images Last week in Florida, at the University of Tampa, President Joe Biden promised to protect and strengthen Social Security and Medicare, as well as lower health care costs. Mandel Ngan/AFP via Getty Images The Medicare wars are back, and almost no one in Washington is surprised. This time it’s Democrats accusing Republicans of wanting to maim the very popular federal health program that covers 64 million seniors and…