He must attack sanctuary cities because the number of deporations is low — below Obama levels. He has been trying to remove more people from the interior of the country and the sanctuary city movement appears to be thwarting that.
ICE removals in the two full years Trump administration (FY2018-2019) have average 262,000, compared with 370,000 in the seven full years of the Obama administration. The number of removals in FY 2019, 267,000, was lower than every but one full year under Obama.
Under Obama, removals became increasingly focused on persons with criminal records, rising from about two-thirds to over 90%, which appears to have continued. ICE boasted that is FY 2019 there was a 110% increase in removal of “family unit members.”
There are about 11 million unauthorized persons in the U.S.
What has changed if anything? The Migration Policy Institute in early 2018 did a deep study and concluded that there has been a “sea change in interior [ie not border[ enforcement, though the total numbers have not changed.
It said that “sanctuary policies are curbing ICE enforcement. ICE relies heavily on state and local law-enforcement agencies to help identify and arrest noncitizens from removal. During the first 135 days of the Trump administration, according to MIP’s analysis. 69% of ICE arrests nationwide were based on transfers from the criminal justice system, mostly state prisons or local jails. This is a decline from the FY 2008-2011, during the peak of ICE activity, when state and local prisons and jails were the origin for more than 85% of ice arrest. The decline is attributable to reduced cooperation with ICE.”
MIP shows that arrests have declinced in California, where the sanctuary city movement is big, and risen in Texas, where it is non-existent.