Inhofe and Thornberry in The Wall Street Journal: Don’t Cut Military Spending, Mr. President

President Trump inherited a military in crisis. The Obama administration asked a shrinking force, with aging equipment and declining budgets, to fight wars and perform other missions around the world. Gridlock on Capitol Hill added to the problem, delivering late and inadequate budgets for nearly a decade. The result was a readiness crisis with tragic, sometimes fatal consequences for American troops.

China and Russia, seeking to make the world safer for authoritarianism, have rapidly modernized their militaries. The U.S. advantage has eroded in key areas: power projection, cyberdefense, space, electronic warfare, air and missile defense, antisubmarine warfare, and long-range ground-based fires. America “might struggle to win, or perhaps lose, a war against China or Russia,” warns the bipartisan National Defense Strategy Commission in a report this month.

The administration’s National Defense Strategy prioritized strategic competition with China and Russia. But to be effective, strategies must be matched with resources. America won’t succeed without sustained, sufficient, predictable military funding.

The past two years have put our military on a better path. In March 2017 Mr. Trump requested $30 billion more in defense spending to begin repairing readiness. His first two budget requests focused on restoring America’s military advantage. Congress followed through this year. For the first time in a decade, we funded the troops in full and on time.

Next year the president and Congress face a critical national-security decision: Will we continue to rebuild our military, or will we squander our progress? Media reports indicate the administration is telling the Pentagon to plan for a $700 billion budget in fiscal 2020. That’s $16 billion less than 2019 and $33 billion less than Mr. Trump’s original budget plan.

Some Democrats may embrace this cut, seeking tax dollars to spend on their own priorities. But our top priority is the troops. Any cut in the defense budget would be a senseless step backward.

The president’s budget is due Feb. 4. A last-minute directive to cut $33 billion from defense would be dangerous. The Pentagon would be forced to cut in areas where the most money can be saved quickly—troops, new equipment, training and maintenance—as it did under sequestration in 2013. Defense Secretary Jim Mattis will be asked to find $33 billion, for example, by planning for lower troop levels, diminishing the U.S. capability to stay ahead of China and Russia, sacrificing readiness—or all three.

Recent reports suggest this proposed $33 billion cut was prompted by concern about the growing national debt. We share this concern. Failing to address this challenge, especially through entitlement reform, will have profound consequences for the economy and national security.

We also acknowledge there is money to be saved in the Pentagon. But deliberate reform—not capricious last-minute cuts—is the way to achieve savings. In the past four years, we have implemented reforms to improve military health care, modernize military retirement and fix Pentagon acquisition. Those reforms and others have resulted in better services for the troops and saved taxpayers billions.

But cutting defense will not close the deficit. The deficit would keep growing even if we eliminated the entire Pentagon budget. The president and Congress should not be duped into a false choice: rebuild our military or accept deep and growing deficits. This was a foolish argument when President Obama made it, and it hasn’t improved with age.

President Trump can prevent this $33 billion cut and the resulting damage by ordering the Pentagon to move forward with the $733 billion budget he originally proposed for 2020. We cannot and should not balance our budget on the backs of America’s troops. Too much is at stake. This is a time to follow through on the progress of the past two years and give our troops the sustained, sufficient, predictable funding they deserve.

Messrs. Inhofe and Thornberry are chairmen, respectively, of the Senate and House Armed Services committees.