Barack Obama

The illegal-immigrant population has begun to tick back up with the improving economy, rising to 11.7 million last year, according to the latest estimates Monday from the Pew Hispanic Center.

Those numbers would appear to contradict claims that the U.S. has control of its borders — a question that is at the heart of the immigration debate in Congress.

SPECIAL COVERAGE: Immigration Reform

Pew, which crunched U.S. government data, said illegal immigration peaked at 12.2 million people in the country without authorization in 2007 and then began to fall, dipping to 11.3 million in 2009 before ticking up again, though at a slower rate than it did during the early part of the previous decade.

Pew said the change is particularly apparent in migration involving Mexico, where a large number of people are going from the U.S. back to Mexico — actually reducing the number of illegal immigrant Mexicans in the U.S.

“This increased return represents a marked change in pattern from the largest immigration wave in U.S. history,” Pew said.

The Obama administration has said the border is as secure as it can be, and pointed to the declining number of illegal immigrants and drop in arrests along the border as evidence. Armed with that data, President Obama has said it’s time to start legalizing illegal immigrants.

But the latest evidence bolsters those who said the poor economy, not a sealed border, was responsible for the drop in illegal immigration. While the numbers don’t prove a link, they do track the same time period as the economy’s downturn and then its slow path upward.

However, Steven A. Camarota, research director at the Center for Immigration Studies, which pushes for stricter immigration limits, said the leveling out and potential increases since 2009 could be due to Mr. Obama’s own enforcement priorities.

He said the administration’s decision not to go after illegal immigrants in worksite raids, and to rejigger enforcement priorities so most illegal immigrants face less danger of deportation, coincide with the trends.

Whatever the cause, Mr. Camarota said the numbers underscore there is still a problem with illegal immigration.

A new report tracking the number of ICE detainers issued confirms that interior immigration enforcement has declined significantly in recent months. This report corroborates my previous analysis of another set of ICE statistics that revealed a considerable deterioration in interior enforcement since 2011.

 WASHINGTON — After weeks of denials, the Obama administration acknowledged Thursday that it had, in fact, released more than 2,000 illegal immigrants from immigration jails due to budget concerns during three weeks in February. Four of the most serious offenders have been put back in detention.

The administration had insisted that only a “few hundred” immigrants were released for budgetary reasons, challenging as inaccurate a March 1 report by The Associated Press that the agency had released more than 2,000 immigrants in February and planned to release more than 3,000 others this month. Intense criticism led to a temporary shutdown of the plan.

The director of U.S. Immigration and Customs Enforcement, John Morton, told a congressional panel Thursday that the agency had actually released 2,228 people from immigration jails over the course of three weeks, starting February 9, for what he described as “solely budgetary reasons.” They included 10 people considered the highest level of offender.