EDITOR'S NOTE: Interested in the marijuana business industry? NJ Cannabis Insider is a new premium intelligence briefing that features exclusive weekly content geared toward entrepreneurs, lawyers and realtors. View a sample issue.

WASHINGTON -- Organizations weighing in on marijuana issues spent $20 million in the first half of 2018, more than triple the $6 million spent during the same period a year earlier, according to an analysis by NJ Cannabis Insider of second-quarter lobbying reports filed with the Clerk of the House.

The increase illustrates the activity on Capitol Hill as several bills have been introduced to remove the federal prohibition against marijuana, or to block Washington from interfering with states that have legalized cannabis.

One bill garnering attention is the bipartisan Strengthening the Tenth Amendment Through Entrusting States or STATES, Act, which was introduced by by U.S. Sens. Elizabeth Warren, D-Mass., and Cory Gardner, R-Colo., and Reps. David Joyce, R-Ohio, and Earl Blumenauer, D-Ore.

"You actually saw a big bipartisan bill in both the House and the Senate," Blumenauer said. "People are talking about it big time."

The measure has attracted eight Senate co-sponsors, including Cory Booker of New Jersey, who also has introduced separate legislation to remove the federal prohibition against the drug. In the House, 22 lawmakers have signed on as co-sponsors.

Groups do not have to disclose how much they spend on particular issues; the figures represent the total expenses for each group that reported that marijuana is one of the issues they're lobbying on.

The number of organizations lobbying on marijuana has increased as well. There were 35 groups that reported lobbying from April 1 to June 30, a 59 percent increase over the 22 organizations registered during the same period in 2017.

Among those weighing in as Congress considers legislation are: the Indiana Farm Bureau; Property Casualty Insurers Assn.; the American Medical Association; and the conservative advocacy group Heritage Action for America.

The National Cannabis Industry Association, the trade group for the legal marijuana industry, increased its lobbying to $280,000 during the first half of the year, up 47 percent over the $191,000 it spent during the same period a year ago.

This report originally appeared in NJ Cannabis Insider. If you are interested in the N.J. cannabis industry, subscribe here for exclusive insider information.

Jonathan D. Salant may be reached at jsalant@njadvancemedia.com. Follow him on Twitter @JDSalant or on Facebook. Find NJ.com Politics on Facebook.