The Pentagon is opposing a $1 billion proposal from U.S. Rep. Joe Courtney, D-2nd District, and his Republican colleague U.S. Rep. Rob Wittman of Virginia that would allow the Navy to build an extra attack submarine in 2022 and 2023.

In a letter to defense appropriators on Tuesday, the second in charge at the Pentagon said the $1 billion in cuts, which would have to be made to pay for the lawmakers' proposal, would disrupt multiple critical defense programs.

"The Virginia-class (attack) submarine provides crucial capabilities to the joint warfight," Deputy Defense Secretary Patrick Shanahan said. However, he added, "we balanced the investments in this capability against other critical capabilities in areas such as space and cyber, and in emerging areas such as autonomy or artificial intelligence" in President Donald Trump's 2019 budget request.

The Pentagon's opposition comes as the U.S. House prepares to vote on its version of the 2019 defense spending bill. The vote is expected to take place Thursday morning.

"It was a surprise because clearly it undercuts Trump's stated goal of a 355-ship Navy," Courtney said by phone Wednesday afternoon.

On the campaign trail and as president, Trump has pledged to build up the size of the Navy, which has set its own goal of 350 ships, including 66 attack submarines.

There are 52 attack submarines in the Navy's fleet today. If the two-per-year build rate continues, the Navy will have 42 attack submarines in 2028. That's because the Navy is retiring older attack submarines, known as the Los Angeles-class, at a faster rate than the newer, Virginia-class attack submarines are being built.

"This is a critical year in terms of whether we give the Navy the tools to take the program to a higher level," Courtney said. "All the testimony we've heard is that they can't keep up with demand requests at 52, let alone 42."

Courtney and Wittman are proposing $1 billion more than what Trump requested in advanced procurement funding to buy long lead time materials, such as nuclear reactor components, for a third submarine in 2022 and 2023, respectively. To find that money, proposed cuts were made to other programs, and those cuts were included as part of the defense authorization bill, which sets spending guidelines and limits, passed by the House in late May.

The Navy is in the midst of negotiating the contract for the next group of attack submarines it wants built from 2019 to 2023. Recent contracts have authorized the building of 10 attack submarines, or two per year. But Navy officials have indicated there is additional capacity in the years 2022 and 2023 to build more submarines.

Shanahan said that the increased costs of building more submarines would mean the Pentagon would have to tap into budgets for other defense programs.

"Combined with the out-year cost of finishing the incrementally funded submarines, the Department would be required to cut over $6 billion from multiple programs such as reducing the buys of Arleigh Burke-class destroyers, oilers and fast frigates," he wrote in the letter to defense appropriators.

Courtney called the $6 billion estimate "total speculation." He and Wittman, who lead the Seapower Subcommittee, which has oversight of Navy shipbuilding, have pushed to build more submarines faster, contending if the Trump administration wants to build up the Navy, it has to spend the money to do so.

j.bergman@theday.com