King County Sheriff John Urquhart flew cross- country from Washington.
With one very clear message for Senators on Capitol Hill.
Sheriff John Urquhart, King County, Washington, "You hear a lot about states rights. Well, this is where the rubber meets the road."
Twenty states and the District of Columbia have legalized medical marijuana.
Washington and Colorado also allow it for recreational use.
Late last month the Department of Justice said it wouldn't interfere with those laws for now.
But that hasn't resolved the banking woes, many marijuana related businesses experience.
Danielle Leigh, NBC News reporter, "Most businesses simply take their excess cash to the bank, but many of these dispensaries can't even get bank accounts, banks don't want to handle the money because its coming from marijuana which is still illegal at the federal level."
Sheriff John Urquhart, King County, Washington, "Anytime you have a cash-only business, I have to respond to robberies."
Colorado dispensary owner Ean Seeb is dealing with that very concern.   He got a notice, this summer that his bank account would be closed.
Ean Seeb, Denver relief co-owner, "It makes day to day operations of a business very difficult."
Kevin Sabet opposes legalizing marijuana.
He argues allowing dispensaries to open bank accounts legitimizes an activity that's illegal at the federal level.
Kevin Sabet, Project Sam Director, "We are on the brink of creating big marijuana, and we have been fighting big tobacco for years."
Sabet plans to tell Senators, the federal government should be closing dispensaries not offering more lee-way.

Tuesday afternoon the Senate Judiciary Committee will hear both arguments as Senators discuss whether to consider new laws that would ease the discrepancies between state and federal laws. 

Several bills have already been proposed in the house.