Hawaii’s two U.S. senators are decrying a Trump administration proposal to trim $1.3 billion from an already lean Coast Guard budget to help pay for a border wall and crackdown on illegal immigrants.

“The proposed reduction of the Coast Guard’s budget by 11.8 percent would directly contradict the priorities articulated by the Trump administration, in particular the president’s priorities regarding enhanced maritime security needs and desire to invest in our nation’s military,” Sens. Brian Schatz and Mazie ­Hirono said in a letter signed Wednesday by a bipartisan group of 23 senators and addressed to the director of the Office of Management and Budget.

As one of five branches of the armed forces, the Coast Guard “plays a vital role in our national security,” and the possible $1.3 billion cut “would result in catastrophic negative impacts,” the lawmakers said.

“We are concerned that the Coast Guard would not be able to maintain maritime presence, respond to individual and national emergencies, and protect our nation’s economic and environmental interests,” they said.

The Coast Guard cut is outlined in a draft budget proposal that is still being developed.

The Washington Post reported the Coast Guard’s $9.1 billion budget would be pared back to $7.8 billion, with the Transportation Security Administration and Federal Emergency Management Agency also in line for budget cutbacks.

For comparison purposes, the Navy early last year submitted a $165 billion fiscal 2017 budget request, while the Coast Guard, which reports to the Department of Homeland Security, asked for $10.32 billion.

The proposed disestablishment of the Maritime Safety and Security Teams created after the Sept. 11, 2001, terrorist attacks to provide protection for strategic shipping “would significantly reduce the Coast Guard’s ability to conduct port security, anti-terrorism force protection, and maritime infrastructure protection,” the letter writers said.

U.S. Sen. Dan Inouye helped commission one of the security teams at Ford Island in 2004. The unit’s mission has changed over the years and it now provides extra boats and personnel for security and law enforcement operations.

More than 1,150 active duty, 150 reserve, 80 civilian and 400 auxiliary personnel make up the Honolulu-based Fourteenth District Coast Guard, which has the service’s largest area of responsibility, covering more than 12.2 million square miles of land and sea.

The Coast Guard is a “lean service” supporting 11 statutory missions worldwide, the lawmakers said. “In 2016, the Coast Guard prevented a record-breaking 416,000 pounds of illegal drugs worth nearly $5.6 billion from entering the United States,” the letter from the senators said.

Central to that effort is the Coast Guard’s “aging fleet’ of high-endurance cutters, medium-endurance cutters and island class patrol boats, and “although the Coast Guard has continued to demonstrate the ability to accomplish more with less, the service’s operational temp is unsustainable as its infrastructure continues to age,” lawmakers said.

Some acquisition has been done, and nine new 418-foot national security cutters are planned to replace 1960s-era cutters, with the seventh and eighth to be based in Honolulu. The Coast Guard commissioned its seventh national security cutter, Kimball, on Saturday. The cutter is scheduled to arrive in Honolulu in 2018. The eighth such cutter, Midgett, is scheduled to arrive in Honolulu in 2019.