Russia’s brazen annexation of Crimea has generated a flood of proposals to reinvigorate NATO. Doing so would make America less secure.

For most of its history, the United States avoided what George Washington termed “entangling alliances.” In World War II and the Cold War, the United States aided friendly states to prevent hostile powers from dominating Eurasia.

The collapse of communism eliminated the prospect of any nation controlling Europe and Asia. But NATO developed new roles to stay in business, expanding into a region highly sensitive to Russia.

The invasion of Crimea has triggered a cascade of demands for NATO, mostly meaning America, to act. President Barack Obama responded: “Today NATO planes patrol the skies over the Baltics, and we’ve reinforced our presence in Poland, and we’re prepared to do more.”

The Eastern Europeans desired much more. An unnamed former Latvian minister told the Economist: “We would like to see a few American squadrons here, boots on the round, maybe even an aircraft carrier.” A gaggle of American policy advocates agreed.

Moreover, Secretary General Anders Fogh Rasmussen said alliance members would “intensify our military cooperation with Ukraine,” including assisting in modernizing its military. A number of analysts would make Ukraine an ally in everything but name.

For instance, wrote Kurt Volker of the McCain Institute, NATO should “[d]etermine that any further assaults on Ukraine’s territorial integrity beyond Crimea represent a direct threat to NATO security and … will be met with a NATO response.” Charles Krauthammer suggested creating “a thin tripwire of NATO trainer/​advisers” to “establish a ring of protection at least around the core of western Ukraine.”

AEI’s Thomas Donnelly proposed “putting one brigade astride each of the two main roads” connecting Crimea to the Ukrainian mainland, “backed by U.S. aircraft.” Robert Spalding of the Council on Foreign Relations advocated deploying F‑22 fighters along “with an American promise to defend Ukrainian skies from attack.”

Senators John McCain and Lindsey Graham urged increasing “cooperation with, and support for, Ukraine, Georgia, Moldova, and other non-NATO partners.” John Bolton suggested putting “both Georgia and Ukraine on a clear path to NATO membership.”

Of course, more must be spent on the military. Ilan Berman of the American Foreign Policy Council complained that “The past half-decade has seen the U.S. defense budget fall victim to the budgetary axe.”

Yet America’s military spending is up 37 percent over the last two decades, while collective expenditures by NATO’s other 27 members are down by 3.4 percent. Overall, the Europeans spend 1.6 percent of GDP on the military, compared to America’s 4.4 percent. Today most NATO members, including the Eastern Europeans–with the exception of Poland–continue to cut outlays.

Of course, U.S. officials insist that Europe should do more. But the Europeans have no reason to change so long as Washington guarantees their security.

Despite Europe’s anemic military efforts, it still far outranges Russia. And with a collective GDP more than eight times that of Russia, the Europeans could do far more if they desired.

The basic problem, noted Stephen Walt, is that “president after president simply assumed the pledges they were making would never have to be honored.” Obviously, an American threat to go to war may deter. But history is replete with alliances that failed to prevent conflict and became transmission belts of war instead.

In fact, in 2008 Georgia appeared to believe that Washington would back it against Russia. Offering military support to Ukraine could have a similar effect.

Washington should bar further NATO expansion. Over the longer term the United States should turn responsibility for Europe’s defense back to Europe.

As I point out in my latest Forbes column: “Americans should sympathize with the Ukrainian people, who have been ill-served by their own government as well as victimized by Moscow.But that does not warrant extending military support or security guarantees to Kiev. Doing so would defeat the original purpose of the alliance: enhancing U.S. security.”

Today Washington could best protect itself outside of the transatlantic alliance.