The only way Trump can get control of illegal immigration is to end sanctuaries. Proposed it to deny them federal funds but the funds come from block grands that other distribute, out of Trump's control. The effect of denying funds may have an unexpected effect that is not desirable. Attorney General should go to the courts to force them to follow federal law.
The sanctuaries give something like this as a reason, “In Los Angeles, home to an estimated 500,000 undocumented immigrants, the police chief stands behind the idea that successful policing requires maintaining the cooperation of the majority of the city's residents. Taking on the role of immigration police would tear that cooperation apart, Los Angeles Police Chief Charlie Beck said in a news conference. “ Their are about 200 sanctuary cities or rather Confederate cities, counties, and state. We fought a civil war over nullification.
Mark Levin 12/1/2016 suggested another approach. Sanctuary cities are applying the principle of Nullification that the Democratic Party argued before the Civil War for states right as related to slavery. Sanctuary Cities, counties, and states have significant Democratic Party rule. Are today's democrats again pulled this trick out of a pocket? "[N]ullification is based on a view that the States formed the Union by an agreement (or "compact") among the States, and that as creators of the federal government, the States have the final authority to determine the limits of the power of that government. Under this, the compact theory, the States and not the federal courts are the ultimate interpreters of the extent of the federal government's power. Under this theory, the States therefore may reject, or nullify, federal laws that the States believe are beyond the federal government's constitutional powers. " https://en.wikipedia.org/wiki/Nullification_(U.S._Constitution)
The new Attorney General should go to the courts to force them to follow federal law. He would have to choose a judge not appointed by Obama that has supported sanctuaries. It is ironic that the case that the Attorney General will site occurred during Obama's first term. The courts ruled against nullification on immigration laws, "The National Government has significant power to regulate immigration," Justice Anthony Kennedy wrote in the majority opinion. "Arizona may have understandable frustrations with the problems caused by illegal immigration while that process continues, but the State may not pursue policies that undermine federal law." http://www.cnn.com/2012/06/25/politics/scotus-arizona-law/index.html and the court decision: rel="noopener">supremecourt.gov/opinions/11pdf/11-182b5e1.pdf
The new Attorney General go into federal court and seek a rit of mandamus compelling the officials of these government to comply with federal law, and if the refuse then hold them in contempt of the court and hold them in criminal contempt of the federal law by name, each and everyone of them. Then we shall see if the courts compel them. Now if the courts do not compel the sanctuaries then no federal law or regulation can be compelled. It is a free for all and any state, city county, school district can ignore federal regulations, bluster, laws etc. and demand federal funds.