There were 12.1 million immigrants [sic] living in the country illegally as of January 2014, according to the most recent estimate from the Department of Homeland Security . The estimates from two independent groups are similar: The Pew Research Center estimates the number at 11.1 million in 2014, and the Center for Migration Studies says there were 11 million people in 2015 living in the U.S. illegally (see Table 1 in the full report).

The most common number offered by our media for the number of people living here illegally seems to be about 12 million. Factcheck.org , published by the Annenberg Public Policy Center, purporting to be a neutral and objective source, cites DHS estimates as well as NGOs:

That would be about 3.5 percent to 3.8 percent of the total U.S. population in 2014.

They even publish this precise-looking graph from Pew:

To be fair, measuring illegal activity is inherently difficult. But the striking thing is that these established authoritative sources pretty much agree on the ballpark. Normally, that establishes a high level of confidence.

But then, how do we square 12 million with the newly released data from the Immigration Reform Law Institute? Paul Bedard writes in the Washington Examiner:

Nearly 40 million Social Security numbers have been stolen and used by illegal immigrants [sic] and others to get work, according to agency records obtained by an immigration reform group. The Immigration Reform Law Institute said that from 2012 to 2016 there were "39 million instances where names and Social Security numbers on W-2 tax forms did not match the corresponding Social Security records." The group said that there is a "thriving black market" used by illegal immigrants [sic] to get Social Security numbers needed to get a job.

Let's allow that a percentage of the stolen numbers were not used by illegals, but how big would that be? Ten percent? Who else has a need for a stolen identity? Well, there are those sleeper agents for foreign powers, like the starring couple in the TV series The Americans, Russians who were trained to pose as ordinary Americans. But there can't be millions of them. I suppose that there are con men and con women exploiting phony identities, but again, how many millions of them can there possibly be?

Being generous to the other groups, there must be at least thirty million illegal aliens using stolen Social Security numbers. How could 12 million illegals account for 30 million stolen identities in the period of 34 years?

Some illegals do end up using more than one number because:

"The Social Security numbers of young children are especially sought by illegal aliens, as this theft is likely to go undetected for years. As children reach late teenage years and apply for credit for cars, student loans, and other needs, they may find that their credit has been compromised with mortgages, credit cards and criminal records attached to their identities," said the group.

But four years is not enough time for such "replacement" numbers to be needed, and the nearly 40 million numbers all appeared in that short time frame.

One thing that we do know: The Obama administration had no interest at all in discovering the magnitude of the problem:

Their report draws attention to a move by former President Barack Obama to stop sending so-called "no match" letters to employers notifying them that numbers used by employees on the wage forms do not match their identity. The change followed the president's decision to approve amnesty for some 700,000 younger immigrants [sic] let into the U.S. under his Deferred Action for Childhood Arrivals. Some of those have been dubbed "dreamers."

Finding out how many people are here illegally is the most basic, necessary step in restoring the rule of law. My guess is that the number is shockingly higher than the estimates FactCheck.org wants us to accept.