U.S. Sen. Cory Gardner brought in $2 million in the three months ending June 30 to fuel his 2020 re-election campaign, besting several Democratic opponents who recently reported fundraising totals.

Gardner’s campaign said the Yuma Republican now has $4.9 million on hand to help defend his seat against about a dozen Democratic challengers in one of the most closely watched U.S. Senate races in the country.

“Senator Gardner’s strong fundraising quarter allows him to continue to build the necessary resources to defeat whichever far-left candidate the Democrats nominate next June,” Campaign Manager Casey Contres said in a statement. “His bipartisan record of results for the state resonates with Coloradans.”

So far, his closest competitor in money totals for the most recent quarter is former state Sen. Mike Johnston, who reported a $1.6 million take and called Gardner’s time in office an example of “failed leadership in Washington.”

“While Cory Gardner has voted with (President) Trump 99 percent of the time and created new problems on everything from immigration to taxes to health care, I’ve spent my life running at the hardest problems and am ready to do that in the U.S. Senate,” Johnston said.

Dan Baer, who has served as a U.S. diplomat and Colorado’s executive director of higher education, raised $1.35 million during the same period.

“I’m a Colorado native who has spent his life serving — both here in Colorado and before that representing President Obama and our country overseas — and has never held elected office,” Baer said in a statement. “That makes this record-breaking $1.35 million report both a historic start for a LGBTQ candidate and a powerful statement that it’s time for a fresh face with a record of public service to represent Colorado in the U.S. Senate.”

Environmental activist Diana Bray, a Democrat who jumped into the race in early April, reported $62,514 raised in the second quarter.

Several other high-profile Democrats trying to unseat Gardner — including former Colorado House Speaker Andrew Romanoff, former Colorado House Majority Leader Alice Madden and former U.S. Attorney John Walsh — have yet to release fundraising totals for the last three months.

They have until Monday to do so.

Gardner, Colorado’s junior senator who was first elected in 2014, is seen as vulnerable after voters in the state handed decisive victories to Democrats in the 2018 midterm elections amid strong anti-Trump sentiment.

The Cook Political Report calls Colorado’s Senate race a tossup, one of only two Republican-held Senate seats to land in that category.