The president has taken an enormous risk and initiated an important national dialogue about the financial woes of the Social Security program. Incredibly, opponents of change have chosen to deny that a problem even exists today and that Congress can avoid action because the problem doesn’t begin until decades from now.

This approach is short-sighted and irresponsible. Like objects in the rear-view mirror, the impact of Social Security’s looming crisis is closer than it appears.

Opponents of change throw out dates like 2042, when the so-called trust fund is depleted or 2018, when Social Security benefits will exceed the taxes collected. Each of these dates is important. However, in reality, the problem actually begins in 2011 — only one year beyond this year’s five-year budget window. Let me explain why:

Since the mid-1980s, the annual payroll taxes collected for Social Security have outpaced benefits paid. This is what is known as the Social Security surplus. Importantly, the annual surplus has grown larger every year. But that is about to change.

This year the government will collect $78 billion more in Social Security taxes than we will pay in benefits. The surplus is expected to expand to $88 billion in 2006, $99 billion in 2007 and so on, peaking at $116 billion in 2011.

At that point, the surplus begins to diminish for the first time, falling to $113 billion in 2012, $106 billion in 2013 and so on down to $85 billion in 2015 and accelerating downward every year thereafter.

This is significant because every dollar collected in payroll taxes is spent, including the surplus. So in 2011, when budget writers are looking at the fiscal 2012 budget, they can count on less Social Security dollars to pad other spending, and the rest of the budget will begin to feel the pinch.

That means defense, education, federal highways, environmental programs — every other area of government will be impacted.

This will happen not in 2018, not in 2042, but just six years from now when Congress will have to make choices between Social Security benefits and other programs. People need to understand this reality.

The president’s fiscal 2006 budget proposes about $60 billion in entitlement savings over five years. This amount, which is relatively small in a $2.57 trillion budget, has already attracted opponents.

In the five-year period from 2011 to 2016, the contracting Social Security surplus will gouge $32 billion out of the rest of the budget and with each coming year remove an accelerating amount as the Social Security surplus continues to shrink.

As unnerving as these impending near-term budget implications may be, they pale in comparison to the underlying structural problems that make the current entitlement system unsustainable.

The Government Accountability Office estimates that the government has made $44 trillion in unfunded promises over the next 75 years. This is a staggering number — almost incomprehensible. To put $44 trillion in context: All taxes raised by the federal government in its history total only $38 trillion.

The three biggest contributors to this growing liability — Social Security, Medicare and Medicaid — are driven by demographics. The financial success of these programs hinged on the idea that there would always be more workers than retirees — a pyramid by which the working generation was financing benefits for the retired generation.

The baby boom generation has upset this pyramid. In 1950 there were 16 workers for every retiree. Today there are 3.3 workers per retiree. But by the time today’s young workers retire, there will only be 2 workers per retiree.

In other words, the pyramid is becoming a rectangle.

To pay the promises we have made, and still maintain a reasonable level of other government programs, our children and grandchildren will face a tax burden double that of today.

That means a tax rate approaching 40 percent of our nation’s gross domestic product, a doubling of the payroll tax and a doubling of income tax rates just to keep up with our current promises.

So while some want to argue the semantics — whether you call it “looming,” whether you call it “crisis,” whether you call it “bankruptcy” — our children are going to face the largest intergenerational tax increase in history if we do not fix this situation.

Unlike Medicare, which has innumerable parts and complicating factors, the Social Security program is simple. A limited number of policy choices are available to make the program sustainable. Personal accounts and benefit changes must all be on the table. The only way Congress will be successful is if everything is considered as part of a bipartisan, comprehensive solution.

It is said that procrastination is the grave in which opportunity is buried. Every year we avoid action means the choices for our kids get tougher.

That is what this is all about. Our own children’s quality of life will be radically reduced — their ability to send kids to college, their ability to buy a house, their ability to buy a car — all would be stifled by the need to support our generation.

Congress must begin work today to avoid this tragic legacy.

Sen. Judd Gregg (R-N.H.) is chairman of the Budget Committee.