Russian nuclear-capable Bear bombers flew inside America’s defense zone near northern Alaska on April 28 and 29, marking the fifth incident of Russian bombers flying against the United States in less than a year.

In June, two Bears were intercepted near Alaska during a Russian military drill involving practice strikes against U.S. missile defense facilities. On the significant date of July 4, two more Bears flew closer to the California coast than any Russian aircraft have since the era of the Soviet Union. Then in February, two Bears circled Guam, a U.S. military hub, and in April Russia flew simulated strikes against U.S. missile forces in Japan.

Analysts say the ramped-up belligerence is part of Moscow’s efforts to sway Washington’s missile defense plans.

Russia has long opposed U.S. plans to complete a Europe-based missile defense system. In mid-March, U.S. Defense Secretary Chuck Hagel announced cancellation of the final stage of the program. Since this was the very stage Russia had most fiercely opposed, pundits viewed the cancellation as a significant concession to Moscow.

At a meeting back in 2012, a live microphone picked up President Obama attempting to privately tell outgoing Russian Prime Minister Dmitry Medvedev that he would have “more flexibility” to negotiate on the Europe-based missile defense system after his reelection. He has since been reelected, and is fast making use of the increased “flexibility.” Incidents like the bomber flights in late April show that concessions to Moscow will only spur Russia to push harder against the U.S.

To understand the geopolitical implications of Russia’s intensifying push against the West, read “Russia’s Dark Rider.”