Janet Napolitano To Resign: 4 Things To Know About The Former Homeland Security Secretary

Janet Napolitano, the head of the Department of Homeland Security (DHS), told senior staff on Friday that she will be resigning from the post in order to become the president of the California public university system. In a statement, Napolitano thanked President Barack Obama "for the chance to serve our nation during this important chapter in our history" and called the opportunity to work with the department "the highlight of my professional career". Obama issued a statement commending her for her "outstanding work" and crediting her with making the American people "safer and more secure...protecting our homeland against terrorist attacks."

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The former Arizona governor took flak from both sides of the immigration debate during her four-and-a-half years as secretary of the DHS, with immigrant advocates embittered by a deportation policy which saw 400,000 shipped out of the United States in 2012 and hawks disgusted with what they saw as her softness on those who entered the country illegally.

1. Under her tenure, 1.6 million deportations took place in Obama's first term.

In 2012 alone, DHS removed some 400,000 people. The president defended the deportations during a November presidential debate, saying they were "criminals, gang bangers, people who are hurting the community, not...students, not...folks who are here just because they're trying to figure out how to feed their families". But according to ICE statistics on removals, 45 percent of the 396,906 removals in 2011 were non-criminal and 24 percent were for misdemeanors.

2. Citing budget concerns, Napolitano and ICE Director John Morton established a policy of "prosecutorial discretion".

They say it was intended to focus department resources on the most serious offenders. In March, the DHS released more than 2,000 undocumented immigrants facing deportation from its jails with tracking devices, prompting a conservative uproar.

3. Agents from US Immigration and Customs Enforcement (ICE) turned against her in August 2012, suing her for violating the Constitution.

The 10 leaders of the ICE union argued that Napolitano and Morton (who also stepped down from his post in June) were overstepping their authority in signing off on Deferred Action for Childhood Arrivals (DACA), an Obama-administration brainchild which gave more than 150,000 DREAMers - young people brought illegally to the US as children by their parents - permission to live and work legally.

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"We are federal law enforcement officers who are being ordered to break the law," said Chris Crane, the president of an ICE union. "This directive puts ICE agents and officers in a horrible position."

That lawsuit was funded by NumbersUSA, a group which advocates for lower numbers of legal and illegal immigration. The attorney on the case was Kris Kobach, the Kansas Secretary of State who in June said of some 200 people who assembled at his home to protest his opposition to a path to citizenship for the undocumented, "It's important we recognize there's a reason we have the Second Amendment. There are situations like this where you have a mob and you do need to be able to protect yourself."

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4. There's going to be a battle over who replaces her.

Many conservatives, especially in the House, want a DHS chief who will do away with DACA and deport DREAMers. Senator Jeff Sessions (R-Ala.), a high-profile opponent of the path to citizenship for the undocumented, said her tenure with the DHS was "defined by a consistent disrespect for the rule of law", adding, "any selection -- interim or permanent -- to replace Secretary Napolitano must disavow these aggressive non-enforcement directives or there is very little hope for successful immigration reform." Republicans who have been filibustering Obama's presidential appointees would likely do so for someone who pledged to continue Napolitano's prioritizations. In response to them, Senate Majority Leader Harry Reid (D-Nev) has threatened to change the rules so that Republicans could no longer use the filibuster for Obama's appointees.