Potential U.S. adversaries have been flexing their military muscles of late, taking provocative action that is specifically directed against the United States and our allies. These actions have important strategic significance. In light of our unilateral disarmament, our potential adversaries are clearly testing our resolve and our military readiness to respond, as well as the Obama administration’s reaction.

On Feb. 15, investigative journalist Bill Gertz reported that two Russian Bear-H Tu-95 strategic strike bombers equipped with nuclear-tipped cruise missiles circumnavigated Guam on Feb. 12 in what can only be categorized as a reconnaissance-simulated strike mission. At some point, they were intercepted by U.S. Air Force F15s operating out of Guam.

It appears to be more than mere coincidence that this provocative mission occurred just “hours” before President Obama’s State of the Union address. Further, it cannot be ignored that this first-of-a-kind mission over vast ocean areas occurred on the same day that North Korea detonated its third underground nuclear device.

Clearly, the Russian strategic bomber flights cannot be viewed as an isolated event. Last summer, Russia sent an Akula class cruise-missile attack submarine to the Gulf of Mexico and operated undetected for an unspecified period of time. We did not find out it was there until after it departed. With Iran’s missile base in Venezuela now operational, according to former ambassador Roger Noriega, the Akula deployment takes on added significance.

Prior to this deployment last June, Russia conducted an exercise of its strategic strike bombers and support aircraft in the Arctic, simulating strikes against our anti-ballistic missile bases in Alaska. Then, in July, a Russian Bear-H TU-95 strategic strike bomber flew into the Gulf of Alaska, most likely simulating strikes against our anti-ballistic bases in California. These Bear-H missions were intercepted by our Air Force and Canadian fighters, hopefully before they reached their simulated missile-launch position.

According to Mr. Gertz, our former United Nations Ambassador John R. Bolton stated that the Russian bomber flights appeared to be part of an increasingly threatening strategic posture in response to the Obama administration’s anti-nuclear policies. He further stated, “Every day brings new evidence that Obama’s ideological obsession with dismantling our nuclear deterrent is dangerous.” I believe it could lead us down a path of strategic instability.

In an article dated Feb. 17, Xinhua reported that Russia plans to strengthen its relationship with China. It was reported that Russian President Vladimir Putin approved a new foreign-policy framework that centers on strengthening the “comprehensive strategic partnerships with China.” This new policy also stated that Russia intends to cooperate with the United States, provided we do not interfere with other nations’ internal affairs.

Russia’s new assertiveness in the Gulf of Mexico and the Pacific could also be an asymmetrical response to our facilitating arms transfer from Libya to al Qaeda-affiliated militias and rebels fighting Russia’s Syrian ally, President Bashar Assad.

Clearly, under Mr. Putin, Russia is reasserting itself in areas where it has had a strategic interest in the past. For example, on Feb. 7, Russian SU-27 jets triggered intercepts by Japanese fighter jets near Japan’s Hokkaido Island. The intercept took place near disputed territory claimed by both countries since the end of World War II.

For more than the past two decades, China has been flexing its military muscle and using bullying tactics to enforce its disputed claims in the South and East China Seas. Fifty-five percent of the world’s maritime traffic transits this key strategic ocean area, which is also thought to hold vast gas and oil resources. The Philippines, Indonesia, Taiwan, Singapore, Japan, Vietnam and Brunei all have claims in this disputed area.

Japan has been involved in an ongoing confrontation with China over the Senkaku Islands. Recently a Chinese frigate used its targeting radar to lock on a Japanese destroyer patrolling in the Senkakus. On Feb. 24, close on the heels of Japanese Prime Minister Shinzo Abe’s Washington visit, the South China Morning Post reported that three Chinese government surveillance ships entered territorial waters off one of the Senkaku’s disputed islands in the East China Sea. Hours before, one of China’s fishery patrol boats deliberately sailed into the disputed zone.

For the record, Japan was given administration over the island as part of the peace treaty signed in San Francisco in 1946. In any confrontation with China over the disputed islands, Japan will look to the United States to invoke the U.S.-Japan Mutual Defense Treaty.

The Obama administration’s reaction to these provocations appears to be one of indifference. The “reset” button with Russia has not altered Mr. Putin’s increasingly hostile trajectory. The disastrous impact of sequestration on our national security will only encourage our potential enemies to take more brazen action and must be reversed. We must not only be perceived as able to meet our global commitments, we must in fact be capable of doing so if we are to deter more aggressive challenges from Russia, China, Iran and North Korea

Retired Adm. James A. Lyons was commander in chief of the U.S. Pacific Fleet and senior U.S. military representative to the United Nations.