Currently I pay about 18% in federal income taxes, and I'd like to be able to be able to check an "opt in" box on my next tax return that would increase my taxes by 2-3% making me eligible for a Medicare type program.
Having a modest salary makes having good health insurance like Medicare available to my family even more important. With this "opt in" option, any American could voluntarily have their taxes increased and have this portion of their taxes dedicated to covering their health care costs provided by Medicare.
If the biggest gripe against a single-payer system is the cost to the government, then I'd be more than happy to chip in a little more to have the security that Medicare offers.
Give 'em hell, Mr. President, millions of Americans are in your corner!