President Trump's executive order on the enforcement of immigration laws calls for a dramatically more aggressive stance on removing illegal immigrants compared to the Obama administration, and will now subject virtually all illegal immigrants to deportation if they have had any run-in with the law.

Obama drew complaints from Republicans when he created the Priority Enforcement Program, or PEP, which was ordered by Obama and announced in the form of a memo from then-Homeland Security Secretary Jeh Johnson. PEP gave local law enforcement officers broad discretion when it came to reporting someone in custody to U.S. Immigration and Customs Enforcement (ICE), and told immigration officials to stand down on deporting a criminal alien because his or her criminal history was still minimal.

Under PEP, those with multiple misdemeanors were treated as a second priority to gang members and those convicted of a felony, and the policy encouraged officials to consider "humanitarian" issues when deciding whether to deport an illegal immigrant.

Specifically, PEP created three enforcement tiers. The first priority were immigrants convicted of a felon, or those suspected of terrorism or espionage. But even then, it said deportation of this group of aliens was "prioritized" unless officials decided there were reasons to let them stay.

Immigrants convicted of three misdemeanors, or major misdemeanors including drug trafficking were put in the second tier priority for removal. A third tier included those who were ordered to leave the country after 2013, but Obama's DHS made it clear that these people were not priorities for removal.

On Wednesday, Trump's executive order changed all that, by removing the tier system and saying priorities are any illegal immigrant who has had any scrape with the law. Trump's order effectively eliminates the wiggle room officials could use to avoid deportations, which was a major theme of the Obama-era policy.

Section 5 of Trump's order holds that as DHS "faithfully" executes U.S. immigration laws, it "shall prioritize for removal those aliens described by Congress" in various parts of the Immigration and Nationality Act. It also specifies six distinct categories of immigrant subject to removal.

They are immigrants who have: been convicted of any criminal offense; been charged with any criminal offense; committed acts constituting a chargeable criminal offense; engaged in fraud against the government; abused U.S. public benefits; been subject to a final removal order.

The order also creates a seventh category that does give immigration officials some discretion, but it's the discretion to make their own call to remove someone, instead of Obama's discretion aimed at keeping people in the country. It says anyone can be subject to deportation if an immigration officer judges that they "pose a risk to public safety or national security."

A senior DHS official told the Washington Examiner that DHS and ICE will have no problem finding criminal aliens even if it is without the cooperation of sanctuary cities.

"If there was a priority to go after criminals that are aliens and they fit the criteria for being removed or criminal investigations, we can find them. There's no hiding that [information]," the official said.