Thomas F. Schaller, professor of political science, writes in his latest Baltimore Sun column, “As Washington politicians search for budget solutions, imagine if there were a magical revenue source that operated not unlike a national consumption tax that many conservatives prefer and would mitigate global warming to please liberals, all while helping repair America’s infrastructure and strengthening our national security, to the delight of almost everyone. Actually, such a tax already exists: It’s called the federal gasoline tax, and it’s been stuck at 18.4 cents per gallon for two decades. We’re long overdue to increase it — maybe even double …