Don't blame them. Blame yourselves.

Over the course of the 20th century, America built its welfare state. It was, by and large, a great achievement, expanding opportunity and security for millions.

Unfortunately, as the population aged and health care costs surged, it became unaffordable. Public debt as a percentage of gross domestic product was around 38 percent in 1965. It is around 74 percent now. Debt could approach a ruinous 90 percent of GDP in a decade and a cataclysmic 247 percent of GDP 30 years from now, according to the Congressional Budget Office and JPMorgan.

By 2025, entitlement spending and debt payments are projected to suck up all federal revenue. Those obligations will lead to gigantic living standard declines for future generations. According to the International Monetary Fund, meeting America's long-term obligations will require an immediate and permanent 35 percent increase in all taxes and a 35 percent cut in all benefits.

So except for a few rabid debt-deniers, almost everybody agrees that we have to do something fundamental. The problem is that politicians have never found a politically possible way to begin. Every time they've tried to reduce debt, they've ended up borrowing more and making everything worse.

So Congress and President Obama set up the "fiscal cliff," an artificial disaster scenario that would force them to do the right thing. Obviously, the negotiations were not going to lead toward the deep structural reforms that will eventually be needed. But they could have begun the reform process. They could have produced a balanced program that would have combined spending cuts and targeted tax increases. They could have reduced Medicare spending on the rich to free up more money for young families.

Obama and House Speaker John Boehner both earnestly wanted to achieve these things. But even the deal that emerged this week in the Senate was discouraging. Not a single hard decision. Little to control spending. Continued low tax rates on families making less than around $450,000 (it is simply impossible to avert catastrophe unless tax increases go below that line).

The White House envisions a series of stages bringing us closer to fiscal sustainability. I hope that's right. But if Congress couldn't make a single tough decision under these circumstances, why should we think it'll make any further down the road? More likely, there will just be more squabbling and brinkmanship, more posturing and punting, which would poison not only future budget talks but also prospects for immigration reform, tax reform, gun control and many other projects.

Whom should we blame for this? Again, we should not blame Obama and Boehner. In their different ways, they and a number of other people in the Congress are trying to find a politically palatable way to deal with these hard issues. They got what conditions allowed.

Ultimately, we should blame the American voters. The average Medicare couple pays $109,000 into the program and gets $343,000 in benefits out, according to the Urban Institute. This is $234,000 in free money. Many voters have decided they like spending a lot on themselves and pushing costs onto their children and grandchildren. They have made it clear that they will destroy any politician who tries to stop them from cost-shifting in this way.

Most members of Congress are responding efficiently to the popular will. A large number of reactionary Democrats reject any measure to touch Medicare or other entitlement programs. A large number of impotent Republicans talk about reducing the debt but are incapable of forging a deal that balances tax increases with spending cuts.

The events of the past few weeks demonstrate that these political pressures overwhelm the few realists looking for a more ambitious bargain. The country either doesn't know or doesn't care about the burdens we are placing on our children. No coalition of leaders has successfully confronted the voters and made them heedful of the ruin they are bringing upon the nation.

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David Brooks' column is distributed by the New York Times News Service.