The coalition trying to ban online gambling in New Jersey hired former U.S. Senate Majority Leader Trent Lott and former U.S. House Republican Conference Chairman J.C. Watts in recent months as it stepped up its lobbying efforts on Capitol Hill, new disclosures show.

The new hires came as two Republican presidential candidates, U.S. Sens. Marco Rubio of Florida and Lindsey Graham of South Carolina, joined other senators last month in introducing legislation to end online gambling in New Jersey, Nevada and Delaware. A similar bill has been introduced in the House, which held a hearing in March.

The effort is led by Las Vegas Sands chairman and chief executive officer Sheldon Adelson, who with his wife gave $93 million to Republican-leaning outside groups in 2012, more than any other donor. His spending included multimillion-dollar donations to super-political action committees supporting GOP presidential candidates Newt Gingrich and Mitt Romney.

RELATED: Will Congress pull the plug on N.J. online gambling?

Las Vegas Sands boosted its lobbying expenses by almost two-thirds to $680,000 during the first six months of 2015 compared with $410,000 during the same period a year ago, according to reports filed with the U.S. House.

The Adelson-funded Coalition to Stop Internet Gambling reported hiring Lott (R-Miss.) and former U.S. Sen. John Breaux (D-La.) in May, and Watts and former Rep. Ron Dellums (D-Calif.) in July.

The coalition did not respond to a request for comment.

In New Jersey, online gambling brought in $120.5 million in its first year of operation, according to the state Division of Gaming Enforcement. Meanwhile, Atlantic City lost four brick-and-mortar casinos.

Among opponents of the legislation, the Poker Players Alliance more than doubled its lobbying expenses, spending $430,000 from January to June compared with $175,000 during the same six-month period in 2014. Caesars Entertainment, which operates an online gambling site for New Jersey residents and is helping to fund the Coalition for Consumer and Online Protection, reported spending $1.2 million this year, down from $1.5 million during the same period a year earlier.

The group "has a broad base of support from law enforcement agencies, child and Internet safety advocates, and state lotteries across the country," spokeswoman Kristen Hawn said. "Sheldon Adelson has said he will spend 'whatever it takes' in this effort, but nothing will change the fact that his bill does nothing to protect consumers or children online and nothing to address the significant black market operating illegally today."

This is a reprint from nj.com. to view the original, click here.