The Coast Guard's top officer said Wednesday that the U.S. can't afford to delay its presence in the Arctic. But lawmakers are eyeing the cash planned for a new icebreaker to fund the wall on the U.S.-Mexico border.

With the November primaries looming, some members of Congress are eager to show their constituents that they support President Donald Trump's plans to build a wall along sections of the southwestern border. That left $750 million for a new heavy polar icebreaker out of a draft of the Department of Homeland Security Appropriations Act.

"I'm going to take a guardedly optimistic approach that ... there's still a lot of interest in getting an icebreaker to replace our 40-plus-year-old Polar Star, which is the only heavy icebreaker in the U.S. arsenal," Coast Guard Commandant Adm. Karl Schultz said at an event hosted by the Center for Strategic and International Studies. "... We need that ship now."

A report released Friday by the Congressional Research Service warns that Russia is increasing its military presence in the Arctic region. The Russians have more than 45 icebreakers, and they're currently working on building a nuclear version, Schultz said.

China has also declared itself a near-Arctic nation and is working on building a new icebreaker. Diminishing ice levels could lead to an influx of traffic in the Arctic in coming years, and there's "increasing mission demand for the Coast Guard up there," Schultz said.

That's as two of the Coast Guard's three polar icebreakers -- Polar Star and Polar Sea -- have exceeded their 30-year services lives, the report states. The Polar Sea is no longer operational, and the need for search-and-rescue and other missions in the region will increase as traffic in the Arctic picks up.

"The reality of the Arctic is on us today," Schultz said. "My thinking is a six-three-one strategy. We need six icebreakers -- three of them need to be heavy icebreakers and we need one today. We need to get going there."

He said Trump's 2019 budget request, which includes plans for a new icebreaker, shows that the Coast Guard's mission in the region is a priority for this administration. The Senate's appropriations draft for DHS still includes the $750 million for a Coast Guard icebreaker, so it's still possible that the service could get the funding in 2019.

Eight House Democrats sent a letter to Rep. Rodney Frelinghuysen, chairman of the House Appropriations Committee, and Rep. Kevin Yoder, Homeland Security subcommittee chairman, criticizing the plan to ditch the $750 million icebreaker funding request, Business Insider reported.

The bill wastes "a staggering $4.9 billion on a border wall and increasing the Immigration and Customs Enforcement budget by $328 million," the letter states, while leaving U.S. national security at a disadvantage for years to come.

The Coast Guard is working with the Navy on plans to acquire three heavy icebreakers for about $700 million per ship.

-- Gina Harkins can be reached at gina.harkins@military.com. Follow her on Twitter at @ginaaharkins.