WASHINGTON — The four-star officers who lead the U.S. military services are urging lawmakers to find common ground and avoid the return of strict, across-the-board spending limits that increase the risk of sending inadequately trained and equipped troops into combat.

Testifying Thursday before the Senate Armed Services Committee, the service chiefs are giving a stark appraisal of the impact of the automatic budget caps known as sequestration. An agreement last year provided temporary relief from sequestration, but the limits return in the 2018 fiscal year.

All the service chiefs say they won’t have the resources to adequately defend the country if sequestration kicks in.

Adm. John Richardson is chief of naval operations. Richardson describes a “triple whammy” that stems from smaller budgets, higher operational demands, and persistent uncertainty about future spending.