“We will all be dead” by the time the U.S. Navy grows its fleet of aircraft carriers to 12 vessels, acting Navy Secretary Thomas Modly predicted in late January 2020.

Under current planning, the Navy won’t grow to 12 flattops until 2065, Modly pointed out during an event at the Center for Strategic and Budgetary Assessments in Washington, D.C.

Seapower Magazine first reported Modly’s comments.

And that’s the best-case scenario. Under the worst case, the fleet might lose carriers instead of adding them.

Modly, who in November 2019 replaced Richard Spencer after Spencer resisted Pres. Donald Trump’s pardoning of a Navy SEAL who committed violent crimes, had spent months prior to his CSBA comments downplaying the likelihood of a major expansion of the U.S. fleet.

In 2016 outgoing Navy secretary Ray Mabus conducted a force-structure analysis that called for 355 ships, up from the previous goal of 308. Trump in 2016 campaigned on a pledge to swiftly grow the fleet.

But expanding the Navy under any administration always was an unlikely proposition. One Congressional shipbuilding expert told The National Interest, on condition of anonymity, that quickly growing the Navy by 75 ships simply by buying new vessels "would be impossible."

Manufacturing and maintaining extra new ships could cost as much as $23 billion a year, according to the Congressional Research Service. For years, the Navy’s annual shipbuilding budget has been around $15 billion.

Adding at least 75 vessels during a hypothetical, two-term Trump presidency lasting eight years would require the administration to plan for, and Congress to fund, as many as 15 new ships every year — six to replace older ships in the process of decommissioning plus another nine to actually expand the fleet.

In 2017, the Navy bought just nine new ships. It purchased 13 in 2018 but planned to request just 10 in 2019. In late 2019 the fleet had 290 ships, up a handful compared to 2016 but still at least 60 shy of Trump's goal.

A December 2019 memo from the Navy to the White House’s Office of Management and Budget acknowledged what experts long had warned. That the 350-ship plan would cost far more than the Navy realistically could expect to get from Congress over the roughly 20-year duration of the expansion.

In the December 2019 memo, the Navy proposed to reduce construction of Arleigh Burke-class destroyers between 2021 and 2025 from 13 ships to just nine. Over the same five-year span, the fleet would decommission early 13 of its 22 Ticonderoga-class cruisers. The moves would save more than $10 billion from an overall $100-billion, five-year shipbuilding scheme.

The net result of the construction slow-down and early retirements would be a reversal of the fleet’s slow expansion since the Obama administration. The Navy’s “battle force” would decline from 290 ships in 2019 to 287 in 2025.

The same mismatch between goals and resources afflicts the carrier fleet. The 2016 force-structure assessment called for 12 large aircraft carriers, up from 11 in the fleet in 2020.

But the Congressional Research Service threw cold water on the 12-carrier plan. According to the CRS, it might take the Navy until the 2060s to stabilize the carrier fleet at a dozen vessels. Even that might be optimistic.

Aircraft carriers are the backbone of the U.S. fleet. Generally sailing in strike groups consisting of at least one cruiser, two destroyers, an attack submarine and a fast supply vessel and embarking an air wing with as many as 70 aircraft, carriers drive the Navy's planning and account for much of the fleet's combat power.

The number of carriers wildly has fluctuated in recent decades. In the late 1980s the Navy maintained 15 carriers -- and 585 other warships -- as part of the Reagan administration's military build-up.

But carriers are expensive. They cost billions of dollars to build and additional billions of dollars annually to man, equip and operate. A new Ford-class flattop costs around $13 billion.

When the Cold War ended, the Navy steadily cut the flattop fleet to a low of 10 vessels in late December 2017. The dip to 10 flattops lasted just eight months before a new, 11th carrier commissioned into service in the summer of 2017.

Now that the Navy is determined to get to, and stay at, 12 carriers, it must face the hard truth. Meeting that goal could prove difficult or impossible. Indeed, the flattop fleet might shrink to a new low of nine ships before it stabilizes at a dozen.

A carrier can serve around 50 years before wear and tear and the need to refresh its nuclear powerplant make its continuing operation uneconomical. Throughout the 1990s and early 2000s, the Navy bought just one carrier every five years, a pace of construction adequate to ensure a 10-carrier fleet over the long term.

The CRS parsed the problem in a February 2019 report.

"Given the time needed to build a carrier and the projected retirement dates of existing carriers, increasing the carrier force from 11 ships to 12 ships on a sustained basis would take a number of years," the CRS reported.

"Procuring carriers on three-year centers—that is, procuring one carrier every three years—would achieve a 12-carrier force on a sustained basis by about 2030, unless the service lives of one or more existing carriers were substantially extended," the research service added.

"Procuring carriers on 3.5-year centers (i.e., a combination of three- and four-year centers) would achieve a 12-carrier force on a sustained basis no earlier than about 2034, unless the service lives of one or more existing carriers were substantially extended.

"Procuring carriers on four-year centers would achieve a 12-carrier force on a sustained basis by about 2063—almost 30 years later than under 3.5-year centers—unless the service lives of one or more existing carriers were substantially extended."

The Navy has made efforts to speed up the pace of carrier purchases. In February 2019 the Navy paid Virginia shipbuilder Huntington Ingalls $15 billion to begin work on two new Ford-class carriers.

CVN-80, the future USS Enterprise, would commission in 2027. CVN-81 Doris Miller, named for a hero of the 1941 Pearl Harbor attack, would commission in 2030.

But even the two-flattop contract doesn't alter the long-term math, according to the CRS. "The Navy projects that under the [fiscal year] 2019 30-year shipbuilding plan, the carrier force would reach 12 ships in FY2022 to FY2024, then drop back to 11 ships and remain there in subsequent years, except for FY2040, FY2042 to FY2044 and FY2046 to FY2047, when it would drop to 10 carriers, and FY2048 (the final year in the 30-year period), when it would drop to nine carriers."

The Navy's only hope to sustainably boost the carrier fleet and avoid the 2048 dip to nine flattops is to consistently spend billions of dollars more than it currently plans to spend as part of the build-up that Mabus originally proposed.

But Modly has been backing away from even Mabus’s plan. “It’s just not sustainable any more,” Modly said. It’s increasingly likely that the 11 carriers the fleet has in 2020 represent a new peak. If anything, the flattop fleet looks likely permanently to shrink in coming years.

David Axe serves as Defense Editor of the National Interest. He is the author of the graphic novels  War Fix, War Is Boring and Machete Squad.