America's future problem won't be too many immigrants, but too few. A "gray tsunami" is coming as the global population simultaneously shrinks and ages, producing an acute worldwide shortage of working-age people.

Immigration reformers must position America now to effectively compete for foreign workers come crunch time.

The biggest obstacle to an immigration expansion thus far has been the notion -- popularized by restrictionists -- that America has been deluged with "mass immigration" since 1965. This line has appealed to people's deep Malthusian intuition that more foreigners would exacerbate the coming population explosion. It was a lie all along: The 3.5 foreigners per 1,000 Americans we have been admitting yearly is significantly less than the 10.4 foreigners we admitted without ill effect at the turn of the last century. It is also far less than the 8.5 foreigners that Canada, Australia, New Zealand and Switzerland admit right now.

Until recently, America had escaped the population decline engulfing Europe and other countries, largely because it has been an attractive destination for immigrants. And their higher fertility rates have compensated for the declining native ones.

But this is no longer the case. According to a Pew Research Center report last month, immigrant births in the United States have fallen in the last five years from 102 to 87.8 per 1,000 women. This has reduced America's overall birthrate to a mere 64 per 1,000 women -- far below replacement levels.

What's more, source countries are themselves experiencing massive population declines. Even India has seen live births per woman plummet from 6 to 2.5 from 1960 to 2009. Mexico has fallen from 7.3 to 2.4. China is on the verge of a historically unprecedented demographic collapse, thanks to its one-child policy.

All this is bad news for America and other Western countries. It will close off the best -- and perhaps the only -- chance to avoid the collapse of the retirement welfare state.

Immigrants, unlike children, start working and paying taxes the moment they set foot on American soil, without requiring expensive schooling and health care. They typically come in their peak working years, when they are young and healthy, and hence contribute to Social Security and Medicare for years before collecting. Even as immigrants bestow this windfall, their energy and inventiveness drive economic vitality and growth.

But the intensifying global demand for young workers will make it far more difficult for America to attract immigrants -- especially since economic liberalization has opened many attractive opportunities for them at home.

The rational response under these circumstances would be to market America aggressively abroad, much like the army does at home to boost sagging enrollments. America should be soliciting applications from young foreigners, even offering them "immigration packages."

To date, immigrants, even highly skilled ones, have radically altered their lives to fit America's immigration policies. They have dutifully applied for their temporary work visas. And those lucky enough to get them have waited patiently for decades for their green cards -- their spouses, all this time, barred from working.

But it will be an immigrants' market soon, in which America will have to fit its policies around their lives. The insanely low cap on work visas for low- and high-skilled immigrants must be scrapped. And the wait to obtain such visas should be counted in hours and days, not months and years.

Unlike in the past, immigrants may not come to settle in America permanently, but rather to work for an extended period before returning home. Currently, most work visas are temporary, forcing immigrants to apply for green cards even if they don't want to stay long-term. The creation of work visas without expiration dates will hand them more options while relieving the artificial pressure for green cards. But of course, those who do want green cards shouldn't have to endure a Kafkaesque hell.

Unfortunately, neither President Obama nor Senate reformers seem to appreciate any of this. Otherwise, they wouldn't be talking about handing the task of determining annual visa quotas to a commission -- with union representatives, to boot. They are paying lip service to immigration. But they act as if America's immigration challenge still consists in turning away foreigners flocking to its doorstep -- not courting them from near and far.

Examiner Columnist Shikha Dalmia is a senior policy analyst at Reason Foundation, a nonprofit think tank advancing free minds and free markets.