MAYOR NUTTER IS prepared to decree that Philadelphia is to be a de facto "sanctuary" city, meaning that U.S. law will be ignored here, at least the part applying to those who are here illegally. Doing so will put Philadelphians at risk.

Any other U.S. laws Philadelphia won't be enforcing?

Treason? Counterfeiting? Skyjacking?

I'm not equating the undocumented with serious criminals, although a few of them are, without doubt. But illegal immigrants made a conscious choice to ignore the process of legal immigration, which means filling out forms, paying fees and waiting their turn.

By their disrespectful, arrogant and self-centered actions, they have made an Undocumented Declaration of Independence - from U.S. laws. To get here they ignore U.S. law, and once here they throw a pity party and demand immunity from other law - such as deportation. Nutter in the past has sympathized with illegal immigrants because Philadelphia is a "humane" city.

Enforcing U.S. law is inhumane? Is that what our mayor thinks?

"Conversations are ongoing with federal agencies, and we do expect to have a resolution in a short time," mayoral press secretary Doug Oliver told me yesterday.

Earlier this week, the Inquirer reported that Nutter is expected to announce that the city will end one year of cooperation with Immigration and Customs Enforcement, under which ICE viewed Philadelphia police arrest records.

Pay close attention: Philadelphia arrest records. ICE isn't pulling random people off the street, and no one gets arrested for traffic violations or spitting on the sidewalk.

Yes, we believe in a presumption of innocence, but these people were in custody.

Under a program known as Preliminary Arraignment Reporting System, ICE checked arrest records to see if any truly bad alien actors were on the list. If so, deportation would follow jail. ICE spokesman Mark Medvesky tells me that ICE has no interest in the status of victims or witnesses. "Our priority is convicted criminal aliens," he said.

With PARS, ICE could find previously convicted felons on the list and alert Philly police. Without PARS, such dangerous people might be released to prey on you and me.

In 2008, in the sanctuary city of San Francisco, Tony Bologna, 48, and his sons Michael, 20, and Matthew, 16, were fatally shot by Edwin Ramos, 20, a beneficiary of the city's practice of shielding illegal-immigrant juvenile felons from possible deportation, according to the San Francisco Chronicle. It is not an isolated case, and it could happen here.

Despite what hysterics would have you believe, there is no mass expulsion of the undocumented. In the last full year of reporting, ending Sept. 31, 2009, 6,350 illegal immigrants were deported, 3,074 of whom had a previous criminal conviction. The 3,276 others were removed for being here illegally, which U.S. law requires.

The numbers are for all of Pennsylvania, Delaware and West Virginia. Philadelphia numbers are not broken out separately.

Now, to satisfy his lofty personal ideal of humanity (above the law), Nutter will put Philadelphians at risk, just as San Francisco did.

Just who is our mayor looking out for?

E-mail or call 215-854-5977. For recent columns: byko.