For all of Obama's insistence on raising top tax rates, the revenue he seeks doesn't begin to solve the nation's fiscal problems.
By 2022, just three programs - Medicare, Medicaid and Social Security - will consume 54 percent of the federal budget, up from 44 percent now, Tanner said.
And "the real explosion of entitlement costs takes place just outside the 10-year budget window."
The Democrats' talk of "cuts" to these programs, which provide a social safety net for many Americans, is also misleading.
Again, these are cuts in the accelerating growth rate of these programs. And if the projected savings from Obamacare don't materialize, the outlook is even worse.
A glance at the budget tables published by the White House Office of Management and Budget puts all the talk about spending cuts in perspective.
Nominal federal outlays fell by $61 billion, or 1.7 percent, in 2012, the first outright reduction since the huge post-World War II declines in 1946-1948.
Inflation-adjusted spending has shown only a handful of year-to-year declines, all small, in the decades since the post-war demobilization.
As Tanner noted, inflation and population growth argue for nominal spending increases. But outlays topped 24 percent of GDP in each of the last four years, the highest by far since World War II and well above the 20 percent historical average.
Since the election, the president has campaigned to raise taxes on the rich, or families making more than $250,000 a year. He has encouraged audiences to write Congress in support of what he says is his election mandate.
Obama needs to ask something more. First, he should explain that there's a wide gap between the benefits to which Americans have become accustomed, especially those for the elderly, and the tax revenue needed to pay for those services.
In other words, Medicare as we know it isn't an option.
Then the president should ask:
What do you want, and how much are you willing to pay for it?
It's something Americans are going to have to decide in the not-too-distant future, so we better start thinking about it now.
Baum is a Bloomberg View columnist. Her email address is cab...@bloomberg.net.