The 2016 Presidential Election season has been one of the most contentious in modern history. There have been many hot button issues that will continue long into the Presidency of Donald J. Trump, and perhaps beyond. There is, however a specific issue that can and must be quickly put to rest. That is the issue of Sanctuary Cities and States!
There are many problems wrapped in this issue, one of which is the Constitutionality of state or local government interference with federal government jurisdiction over immigration. State and local leaders who argue that their cities will serve as sanctuaries know that they are in violation of Article VI, Clause 2 of the United States Constitution which provides:
This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding. 
Known as the Supremacy Clause, this language means that a law of any state or local municipality that is contradictory to federal law is not valid. State and local elected officials know this to be true. Standing on ceremony while claiming a municipality to be a Sanctuary City or State, is an effort to garner favor with a segment of society for political purposes.
So, how does the U.S. Congress enforce the Law of the Land when states and municipalities resist? The Constitution also provides in Article I, Section 8, Clause 1 of the Constitution:
The Congress shall have the Power to lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defense and Welfare of the United States; but all Duties, Imposts and Excises shall be uniform throughout the United States.
The Spending Clause gives Congress the power to appropriate funds to the states to provide services for the people. In appropriating these funds, Congress has the power to attach certain conditions to the provisions. This practice is quite common and is used as a carrot to entice states to doing what the Congress wants them to do, or as a stick prodding local and state leaders into compliance with federal laws without involving the judicial branch. One such instance is the landmark U.S. Supreme Court case of South Dakota v. Dole. Congress passes legislation giving the Secretary of Treasury the power to withhold 5% of federal highway funds from those states that did not make the legal drinking age 21 years. South Dakota argued that this rule was unconstitutional use of the Congressional spending power. Chief Justice Rehnquist delivered the opinion of the Court as follows:
Congress may achieve its objectives by conditioning the receipt of federal funds upon compliance by the recipient with federal statutory directives under its spending power. The spending power has three general restrictions. First, the exercise must be in pursuit of the general welfare. Courts should defer to the Congress’s judgment about this requirement. Second, conditions on the receipt of funds must be unambiguous, so states can exercise their choice knowingly and be aware of any consequences. Finally, the conditions on grants must relate to the federal interest in particular nationwide projects or programs. Here, all three conditions are met. First, the legislation is for the general welfare. Second, it is set in unambiguous terms. Third, it is directly related to safe interstate travel, one of the main purposes for which highway funds are expended.The financial inducement here is not large enough to be considered coercive, as only a small percentage of highway funds are involved.
The rule of law from Dole is that the Spending Power of Congress has three general restrictions: (1) the spending power must be used for the general welfare; (2) the conditions must be unambiguous, allowing the states to make a knowing choice and be aware of the consequences of the choice; and (3) the conditions must be related to a federal interest in nationwide programs or projects.
In a nutshell, Congress has the power to begin cutting funds from states and municipalities that continue to serve as Sanctuaries to those in the United States illegally. So long as the funds being cut are not already budgeted as part of other legislation or service packages, Congress can use a “carrot and stick” approach. States and municipalities that choose to go down the road of defiance to further a political goal run the risk of hurting their own constituency. If that is the path they choose to walk, then they have no one to blame but themselves when the people vote them out of office!
 U.S. Const. art. VI, cl. 2
 U.S. Const. art. I, § 8, cl. 1
 S. Dakota v. Dole, 483 U.S. 203 (1987)