The number of native-born, working-age Americans who aren’t working has shot up by almost 9 million since 2007, and by almost 15 million since 2000, according to a new report by the Center for Immigration Studies, a group that favors reduced immigration.

By late 2012, roughly 50 million native-born working-age Americans weren’t working, up from roughly 36 million in 2000, according to the March 13 report, titled “Still No Evidence of a Labor Shortage.”

The army of idle Americans is important for the immigration debate, because advocates for greater immigration say foreign workers are needed to fill slots that can’t be taken by Americans.

The 50 million idle Americans include many who are studying, have chosen not to work or have retired early.

But the government data shows that 16.7 million native-born Americans wanted — but did not have — full-time work in 2013, up from 10.5 million in late 2007, and 7.8 million in 2000.

These unemployment and underemployment numbers include all native-born Americans who sought work in the last few weeks, are working part-time while seeking full-time jobs, and those who are “marginally attached” to the workforce.

The rise in the number of unemployed Americans was accompanied by increased employment of immigrants.

The data shows that 23.8 million immigrants had jobs in 2013, up slightly from 23 million in 2007, and up sharply from 18.8 million in 2000.

The shift in employment patterns underlies the numerous polls that show rising opposition to any amnesty for illegal immigrants, and that show lopsided opposition to further inflow of immigrants and guest-workers.

A March 13 report by Gallup showed that only 4 percent of Americans regard immigration as the top problem facing the United States. The poll did not say if the four percent want more or less immigration. Unemployment and the economy was deemed most important by 36 percent of the 1,048 adult respondents.

The opposition to increased immigration may have played a role in the March 11 win by Republican Rep. David Jolly, who slammed his opponent after she supported greater use of migrant workers.

“We have a lot of employers over on the beaches that rely upon workers and especially in this high-growth environment, where are you going to get people to work to clean our hotel rooms or do our landscaping?” Sink told her audience Feb. 25.

Subsequently, Jolly ran a TV ad in the district, saying “on illegal immigration, I favor stronger borders. Not amnesty.” He won the district, even though he was outspent and 50.7 percent of the district’s voters pulled the lever for President Barack Obama in 2012.

The opposition to amnesty gives the GOP an opportunity to leapfrog over the Democrats, according to Sen. Jeff Sessions.

“Republicans have a choice… [because they] can either join the Democrats as the second political party in Washington advocating uncontrolled immigration, or they can offer the public a principled alternative and represent the American workers Democrats have jettisoned,” he wrote in a March 13 article, titled “Becoming the Party of Work.”

“Republicans can either help the White House enact an immigration plan that will hollow out the American middle class, or they can finally expose the truth about the White House plan and detail the enormous harm it will inflict,” he wrote.

“Is it not time for the GOP to make a clean public break from the special-interest immigration lobby and let Democrats own — solely, completely, and exclusively — the unwise and unpopular policies they are pushing on these groups’ behalf?” said Sessions, who may be preparing for a presidential run.

“The heart of the GOP’s pro-worker, pro-middle-class agenda should be a bold reforming of our welfare system… [and] should be combined with a series of conservative policies all united by that common theme: shrinking the welfare rolls and growing the employment rolls,” he said.

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