U.S. Sen. Cory Gardner, the Colorado Republican, and his Democratic challenger, former Gov. John Hickenlooper, each released new TV ads Tuesday focused on what could be central issues in the 17-week sprint to Election Day.

“In the middle of a health crisis, why is the Trump administration in court to get rid of people’s protections for pre-existing medical conditions? It’s lunacy,” says Hickenlooper in his new 30-second ad. “When I was governor, we got health coverage for 500,000 more Coloradans.”

The ad doesn’t mention Gardner, who hasn’t said whether he supports a Trump administration lawsuit to overturn the Affordable Care Act, but Hickenlooper closes by saying he approves the message “because we’ve got to stop fighting about health care and get to work lowering costs.” 

The new Gardner 30-second ad, featuring the senator and his family packing an SUV after what appears to be a getaway in the mountains, highlights last month’s Senate passage of a Gardner bill to permanently fund the Land and Water Conservation Fund and provide millions to catch up on maintenance in national parks.

“Once again, Sen. Gardner has delivered for the millions of Coloradans who enjoy the great outdoors,” said campaign spokesman Jerrod Dobkin in a statement. “Gardner continues to prioritize what’s best for Colorado by leading the bipartisan charge to fix our national parks with the backing of the nation’s leading conservation groups.”

Strategists expect Hickenlooper to take a page from the Democrats’ successful 2018 campaign by hammering Gardner and the Republicans on health care, including GOP efforts to overturn the popular legislation known as Obamacare.

Likewise, Gardner, running on a ticket with Trump in a state where the president is deeply unpopular with voters, will likely continue highlighting bipartisan accomplishments like the Great American Outdoors Act, which drew praise from conservation groups that are typically opposed to the incumbent and his environmental record.

Both candidates’ opponents swung hard at the ads.

“You’ve got to be kidding me,” Hickenlooper tweeted after viewing Gardner’s ad. “Senator Gardner is going on vacation in his new TV ad as thousands of Colorado families are struggling to pay their bills. He needs to be back in Washington working on COVID relief, not deceiving Coloradans about his toxic record.”

The Colorado Sierra Club, which urged Democrats to back the bill Gardner touts in the new ad, took to Twitter Tuesday to list instances when Gardner supported Trump’s environmental policies and voted to cut funding for the program he’s bragging about saving in the ad.

“Long story short, Senator @CoryGardner’s voting record and policies don’t match the rhetoric in his ad,” the organization tweeted. “Coloradans shouldn’t have to wait for Gardner and Trump to protect our public lands whenever it’s most politically convenient.”

Republicans were having none of it, with Dobkin suggesting the Colorado Sierra Club should check out an article about the club’s support for Gardner’s legislation and Matt Whitlock, senior advisor to the National Republican Senatorial Committee, accusing the group of “[p]utting your partisanship ahead of accomplishing your policy goals.”

Gardner turned Hickenlooper’s jibe back on his challenger, invoking Hickenlooper’s recently imposed ethics violation for accepting a ride in a fancy Italian limousine while attending an international conference.

“John Hickenlooper is now campaigning *against* outdoor recreation in Colorado,” Gardner tweeted. “Maybe it’s just because he can’t figure out how to fit all this camping stuff into a Maserati.”

Hickenlooper’s ad got less pushback.

Joe Jackson, spokesman for the Colorado GOP, said in a statement to Colorado Politics: “John Hickenlooper is just trying to deceive voters about his support for a massive government takeover of healthcare, which will only result in less choice. At the end of the day, Coloradans know that Hickenlooper will ultimately follow AOC and Washington Democrats in supporting socialized medicine.”

Jackson was referring to U.S. Rep. Alexandria Ocasio-Cortez, the New York Democrat who supports the single-payer Medicare for All proposal opposed throughout the campaign by Hickenlooper.

Gardner has leveled a similar attack against Hickenlooper, who was booed by Democrats in California when he was running for president a year ago and said the party shouldn’t get behind policies like Medicare for All. Romanoff, too, made his primary rival’s stance against “socialized medicine” a central issue his bid for the nomination.

The Colorado Senate race, which could determine which party holds the majority after the November election, is shaping up to be one of the hardest-fought and most expensive in the country this year.

Hickenlooper won the Democratic nomination last week after a bruising primary battle with former state House Speaker Andrew Romanoff, while Gardner, considered the most vulnerable Republican senator on the ballot this year, was nominated for a second term without opposition.