How else to explain the sudden increase of bombers in the skies over Europe, kidnapped spies, troop buildups in Eastern Europe and roaming submarines in the Baltic Sea?

Much of what we see today, we hope, is bluster, as when a popular Russian television host reminded his prime-time audience that Russia could reduce the United States to "radioactive dust" (to help explain why President Obama's hair was graying).

But something has indeed been afoot since Vladimir V. Putin resumed the presidency of Russia in 2012 and sought to push back against the West, which he has accused of meddling in Russia's backyard.

Here are recent examples of Russia's new assertiveness. Of course, none of this has been confirmed by Moscow.

Air

In response to an "unusual level of air activity over European airspace," NATO scrambled fighter jets to intercept 26 Russian aircraft in just two days this week, including 19 Russian fighters, bombers and refueling aircraft on Wednesday.