"By providing law enforcement agencies with surplus military equipment free of charge, the NDAA encourages police to employ military weapons and military tactics." -- http://www.newsweek.com/how-americas-police-became-army-1033...

'[The 1033 Program] "permits the Secretary of Defense to transfer, without charge, excess U.S. Department of Defense (DoD) personal property (supplies and equipment) to state and local law enforcement agencies (LEAs),"' -- http://www.washingtonpost.com/blogs/wonkblog/wp/2014/08/14/t...

Caveat: "given" may be the wrong term: 'Estevez said that such equipment is "conditionally loaned" to the local police departments and is returned to the Department of Defense for "demilitarization at the end of its useful life."' -- http://www.military.com/daily-news/2014/09/10/official-most-...

It's also definitely worth noting that the majority of items aren't tanks, though: "Requisitions cover the gamut of items used by America’s military -- clothing and office supplies, tools and rescue equipment, vehicles, rifles and others small arms. Of all the excess equipment provided through the 1033 program, only five percent are weapons and less than one percent are tactical vehicles." -- http://www.dispositionservices.dla.mil/leso/Pages/default.as... (Though if that <1% is in terms of number of items rather percent of total value, that may still be a misleadingly small percentage.)