What do US police need tanks, bazookas, and machine guns for?

It's been going on for two decades now and the trend is accelerating
...The militarization of US police.
What do local police departments need tanks, bazookas, and machine guns for? As the US government becomes more aggressive overseas, it's also developing its military capacity to repress American citizens at home. To know what is really going on in the U.S., watch this video at: Ahmed Ismail