Five years of arbitrary defense spending caps have taken a toll on U.S. military might. Every one of the service branches is today smaller and in worse shape than when Congress passed the Budget Control Act of 2011.

That might not be so dangerous if the world were a safer place. But it’s not. Congress needs to get serious about rebuilding our depleted military, and it needs to start now. It will take years to repair the damage done to our defense forces.

How bad is it? Let’s look at our ground forces first.

Since 2012, the Army has shrunk from 45 combat brigades to only 31. In February, Gen. Daniel B. Allyn, , informed the House Armed Services Committee that only a third of those brigades are considered combat ready and only three, count ‘em, three, would be able to deploy immediately to a combat zone.

The Marine Corps is shrunken, too. Its end-strength now stands at about 184.400—down from 202,000 five years ago. Training and equipment are woefully sub-par, as well.

Inadequate funding has hit Marine aviation units especially hard. Maintenance crews have to cannibalize some planes to keep others flying.  Last December, only two out of every five Marine aircraft were even flyable. Assistant Commandant of the Marine Corps Gen. Glenn Walters warns that today’s Corps “is insufficiently manned, trained and equipped across the depth of the force to operate in an ever-evolving operational environment.”

Things aren’t much better for our air and sea forces. The Heritage Foundation’s Index of Military Strength assesses the Air Force as being 24 percent short of the 1,200 fighter jets it needs. As for keeping the aging aircraft it does have flying… it lacks 1,000 pilots and over 3,000 flight maintenance crew members. Only four of its 36 combat-coded squadrons are ready to execute all wartime missions.

The Navy has shriveled to 276 combat ships—the smallest U.S. battle fleet since before World War I. And the readiness of the force continues to decline. In February, Adm. William Moran, Vice Chief of Naval Operations, testified before the House Armed Services Committee that “the Navy’s overall readiness has reached its lowest level in many years.”

His testimony was subsequently affirmed by a series of accidents that revealed a deplorable decline in basic seamanship. First, the USS Lake Champlain collided with a fishing vessel. Then the USS John S. McCain and the USS Fitzgerald hit cargo ships, costing 17 American sailors their lives.

All of these ships were part of the Navy’s Forward Deployed Naval Forces, considered our most proficient, well-trained, and experienced force because they’re operating all the time. But a report issued last month by the Government Accountability Office found that little to no dedicated training periods were built into the operational schedules. As a result, 37 percent of the warfare certifications for cruiser and destroyer crews based in Japan—including certifications for seamanship—had expired.

While U.S. military strength and readiness has declined across the board, other nations have been ramping up their forces. And these nations are not our friends.

While U.S. defense spending is lower than it was five years ago, China has increased its military budget by more than 10 percent in each of the last five years. Its standing army is 56 percent larger than ours, it is fielding a stealth fighter to compete with our F-22s and is rapidly building a blue-water navy.

Beset by economic woes, Russia is now putting the brakes on its military build-up. But it has successfully propped up Assad’s terrorist supporting regime in Syria. Moscow also continues to occupy Ukraine and intimidate our NATO allies by sending warships into their waters, buzzing their fighter aircraft and increasing its stockpile of tactical nuclear weapons.

Meanwhile, North Korea has become a nuclear power in its own right and is rapidly closing in on its goal of being able to deliver nuclear warheads to any spot on the planet.

The U.S. remains the world’s most dominant military power. But that power is dwindling rapidly, challenges are growing, and old allies are not what they once were. Washington must act now to start turning this dangerous situation around.