Barack Obama gave four speeches last night. The first was the same optimistic cry for change that has carried him so far in this Presidential season. The second was a tough, frontal attack on the economic and foreign policies of both George Bush and John McCain. The third was a (Bill) Clintonesque bit of social policy triangulation—we can all work together to find solutions to such hot button issues as abortion, guns, gay marriage, and immigration. The fourth was a recitation of his economic agenda—a long list of promises that is familiar to readers of TaxVox by now.

Still, heard all at once, this catalogue is breathtaking:, universal health care, higher education for every child, more money for early

childhood education, rebuilding the military, $150 billion for alternative energy research, and tax cuts for small business and for "95 percent of all working families."

Last night, he insisted he would pay for it all. But how? All he told us was that he'd end the war in Iraq, close corporate tax loopholes, and eliminate wasteful and obsolete government programs.

This is, of course, impossible.

It being the most political of speeches, Obama left out a few things. He never said, for example, how much he'd tax the unlucky (or lucky, depending on your point of view) 5 percent. He never mentioned that his key tool for achieving energy independence in 10 years is an auction of carbon permits that is equivalent to a massive tax on fossil fuels.

It all sounded so hopeful. So painless. So, may I say, audacious.

I get that politics is a short-term business and that fiscal responsibility is a stone cold electoral loser. However….

Obama spoke eloquently last night about our moral obligation to future generations. And he may mean it. But there is a stunning irony in all this. These trillions of dollars of unfunded promises will have to be paid for eventually. As it happens, much of the tab will end up in the laps of the very 20-somethings who are so enamored of Obama's vision for the future.