[UPDATE: see the questions for those using the study]

In the Washington Post, former INS head Doris Meissner (now with MPI, the Migration Policy Institute) offers "Moving beyond illegal immigration enforcement policies" ( peekURL.com/zFtrqQp ):

Illegal immigration and enforcement have been the dominant concerns driving immigration policy for more than 25 years. Deep public skepticism over the federal government’s will and ability to enforce the nation’s immigration laws has come with them. As a result, "enforcement first," a proposition that argued for effective enforcement as a precondition to broader reforms, became widely embraced.

In a report released Monday, the Migration Policy Institute documents how dramatically facts have changed from those long-held perceptions. Particularly since Sept. 11, 2001, but dating to the 1986 Immigration Reform and Control Act (IRCA) - which attempted to end illegal immigration through employer sanctions, increased border enforcement and legalization - the nation has made unprecedented, steep investments in the capacity of federal agencies to aggressively enforce immigration laws.

Since the 1986 legislation was enacted, nearly $187 billion has been spent on immigration enforcement. Budgets for the two main federal enforcement agencies - U.S. Customs and Border Protection (CBP) and U.S. Immigration and Customs Enforcement (ICE) - and its primary enforcement technology initiative, the U.S. Visitor and Immigrant Status Indicator Technology (US-VISIT) program, are nearly 15 times what was spent to operate the U.S. Immigration and Naturalization Service in 1986.

Today, the federal government spends more on its immigration enforcement agencies than on all its other principal criminal law enforcement agencies combined. Spending for Customs and Border Protection, Immigration and Customs Enforcement, and US-VISIT reached nearly $18 billion in fiscal 2012. Contrast that with the $14.4 billion spent for the FBI, Drug Enforcement Administration, Secret Service, U.S. Marshals Service and the Bureau of Alcohol, Tobacco, Firearms and Explosives.

You can read the report - ominously entitled "Immigration Enforcement in the United States: The Rise of a Formidable Machinery" - at migrationpolicy . org/pubs/enforcementpillars.pdf (authors: Meissner, Donald M. Kerwin Don Kerwin, Muzaffar Chishti, and Claire Bergeron).

In government terms, $187 billion over 26 years isn't that much. While I welcome being corrected, a brief glance at the report doesn't show them attempting to break out how much of that amount is due to actual immigration enforcement rather than all the other things that CBP and ICE do. That includes manning customs stations and, more importantly, helping fight the "War on Drugs". It also - of course - doesn't admit that a good part of immigration enforcement is just a "Big Show on the Border" that's designed to fail.

UPDATE: ask these questions of those using this report to reduce immigration enforcement or push amnesty.

UPDATE 2: From this:

The agencies do not disclose the amounts they spend on immigration specifically, but the last separate budget of the Customs Service, in 2003, was $3.5 billion, or about $4.4 billion in 2012 dollars. Simply subtracting that amount from the total spending on "immigration enforcement" would negate the MPI study's central finding.

UPDATE 3: MPI responds to Mark Krikorian's points (last link) in this PDF: peekURL.com/z9W2Jyb Summary: they got nothin'. But, they did spend two years on the report; two years of their supporters' money they spent on something that can't be accurately determined since government agencies don't break out specific things they spend their money on.