"We're running out of places to drill on land and in shallow water," President Obama said in his Oval Office address. Fortunately, it's not true. Yet his effort to use the oil spill to justify moving away from oil entirely and replacing it with alternatives is a bad idea for the American people.

Now, if the president meant "running out of places that we haven't declared off limits," then yes, technically, what he said was true. And therein lies the problem: We've managed over the years to cut ourselves from many potential energy sites - ones that could be accessed more cheaply, easily and safely than the deepwater BP site that's been leaking for weeks.

This isn't mere conjecture or wishful thinking. According to the Department of the Interior, huge onshore deposits of energy can be found on federal lands. Yet much of this energy is either explicitly off-limits or hampered by regulatory constraints that effectively make it so. Part of the solution to the risk of offshore spills - as well as high oil and natural gas prices - lies right under our feet. But Congress won't change the laws that keep this domestic energy locked up.

Indeed, the more we look for oil and natural gas in the United States, the more we find. If only we were allowed to go and get it.

Federal lands are critical to the energy policy debate because most of America's onshore energy is located in the West and in Alaska, where more than half the land is under federal control. Such lands, the Interior Department estimates, "contain 31 billion barrels of oil and 231 trillion cubic feet of natural gas." Thirty-one billion barrels of oil represents 50 years of current imports from Saudi Arabia and 231 trillion cubic feet of natural gas is enough to supply all of America's households for 46 years.

However, "just 8 percent of onshore federal oil and 10 percent of onshore federal gas are accessible under standards lease terms," Interior notes. The rest is either restricted outright or subject to considerable amounts of red tape. Among the former: Alaska's Arctic National Wildlife Refuge, where an estimated 10 billion barrels of oil lies beneath a few thousand acres at the edge of this nearly 20 million acre refuge.

Granted, few Americans want unrestricted oil and natural gas wells in our treasured national parks or other areas of scenic, environmental or historical significance. However, the drilling restrictions on federal land far surpass such reasonable limits. This is especially true given the advances in drilling technology that have dramatically reduced both the above-ground environmental footprint and the risk of spills.

Even more energy lies offshore. Some 86 billion barrels of oil and 420 trillion cubic feet of natural gas are beneath America's waters, Interior says. Of those amounts, 19.1 billion barrels of oil and 83.9 trillion cubic feet of gas lie in federally controlled territorial waters that are completely off-limits to leasing and development.

The actual volumes of onshore and offshore energy could be far greater - Interior's initial energy estimates tend to be low. This is especially true of the off-limits areas, which haven't been thoroughly explored.

Many activists and politicians insist that America's untapped oil and gas reserves are merely a "drop in the bucket" and therefore not worth the bother. But these Interior estimates put the lie to this claim.

Clearly, the president hopes to parlay the oil spill into "cap and trade" legislation designed to raise the price of (and thus diminish demand for) oil, ushering in the age of alternative energy sources to replace it. But the oil spill doesn't change the fact that alternative fuels and vehicles have economic and environmental problems of their own. The reality is that the age of petroleum is going to be with us for a while longer, and every barrel that isn't produced nearby must travel great distances via tanker. And, according to a National Academy of Sciences study, the risk to tanker spills is considerably greater than spills from offshore wells.

With President Obama urging action on a new energy bill, it's high time we asked why we're ignoring the significant amount of energy we have right here in America. Can we afford to keep putting it off limits? The sad fact is, we can't. We need to make this energy available to the American people.

Ben Lieberman is a senior policy analyst in the Roe Institute for Economic Policy Studies at The Heritage Foundation.