Today Ukraine is threatened by a large Russian force on its border. The Crimea has been annexed by Russia, and Russian forces are consolidating their hold on the province. Despite assurances by the Russians that they have no interest in invading Ukraine, it is easy to be dubious of their claims. Capability doesn’t lie, and intent can change in a heartbeat.

Many have already said that there are no military options in the Ukraine crisis. While Western Europe and the United States do not desire conflict with Russia, the lack of action supporting Ukraine is actually a provocative gesture that invites escalation by the Russians. Fritz Kraemer, a little-known but highly influential strategist in the Pentagon best known for his many years as advisor to numerous secretaries of defense, believed that there were two ways to be provocative. One way was to be threatening, and in so doing provoke an enemy to action. The other way was to appear weak, and thus to provoke an adversary into a similar risky misadventure.

Before the United States Air Force began pounding Saddam’s forces in what would be a prelude to a one-hundred-hour ground campaign, it provided a much more subtle service to the Kingdom of Saudi Arabia. When considering the first Iraq war, most people think about the offensive campaign that pushed Saddam’s forces out of Kuwait. Few remember the deterrence provided by airpower before allied aircraft began the offensive that would be known as “Desert Storm.”

On August 2, 1990, Iraq invaded Kuwait. Almost immediately the threat to Saudi Arabia was recognized in the United States. On August 7, the first contingent of F-15s were deployed to Saudi Arabia. These aircraft provided a stopgap to prevent Iraqi aircraft from supporting a ground invasion of Saudi Arabia. It also bought time to work diplomatic initiatives, and sought to quell the Saudi’s fear of an impending invasion.

This was just one of many examples where the United States has used military deployments to deter an adversary. During the Kennedy administration, the Soviet Union issued an ultimatum to the Western powers calling for the withdrawal of all military forces from Western Berlin. Then on August 13, 1961 the East Germans began constructing the Berlin Wall. Kennedy went to Congress and asked for an increase in the defense budget and authorization to boost the end strength of the Army to one million men. In October and November of 1961, the United States began the largest deployment of Air National Guard interceptors to Europe in an operation dubbed “Stair Step.” This served to dissuade further Soviet aggression, and though the Wall remained it would ultimately be torn down.

These examples highlight the importance of the military lever of national power in support of diplomatic efforts when faced with an adversary determined to use military force. Unless backed by a credible use of force, negotiations will often fail. Foreign-policy practitioners frequently dismiss the military as an option, because they prefer “soft power.” These same practitioners consider “hard power” to be inherently provocative. Yet, deployments of military forces need not be escalatory, especially when they are intended to be defensive in nature.

Crimea is most likely permanently lost until there is a change in government in Russia. To buy time for Ukraine and to allow time for diplomatic measures to be effective, a military solution is called for. A purely defensive deployment of F-22 fighters (along with supporting aircraft) is just one possible solution. To be diplomatically effective these forces would have to come with an American promise to defend Ukrainian skies from attack.

Without firing a shot, such a deployment would immediately change Putin’s invasion calculus. Faced with F-22s, Russian aircraft would not survive, and thus could not support a Russian ground invasion. Ukrainians would feel more confident about their ability to defend their country, since any Russian invasion would be subject to attack by Ukrainian aircraft protected by F-22s.

The resulting pause and collective exhale would allow all sides to consider a future where an aggressive Russia will be met with firm American resolve. Furthermore it puts some teeth into what everyone believes is the “strong message that needs to be sent to Putin,” rather than just sending the Ukrainians some groceries.

To those that wonder about the outcomes from what they would surely term a severe provocation without a clear understanding of United States’ interests, I propose three. First, Putin and others would be put on notice that unilateral attempts to militarily change the post-World War II global order will be forcefully countered. Second, countries that rely on American power as an alternative to developing their own nuclear-arms program would feel confident that the United States will honor its commitment to extended deterrence. Finally, the countries that have heretofore been prevented from joining NATO by a belligerent Russia can comfortably enter the global commons without fear of coercion.

Robert Spalding III is a Military Fellow at the Council on Foreign Relations. Mr. Spalding was most recently vice commander of the 509th Bomb Wing based at Whiteman Air Force Base, Missouri, where he was responsible for preparing and maintaining United States' only B-2 wing. He also commanded the 509th Operations Group, where he launched B-2s to protect civilians during Operation Odyssey Dawn.