Margaret Warner: Hello, I’m Margaret Warner. Welcome to our Trendines special, a PBS NewsHour collaboration with Al-Monitor, a website of news, analysis and opinion on the Middle East.

The crisis in Ukraine — and the intense diplomacy over it — has dominated the world’s attention in recent weeks. Today, we explore the impact it may have in the Middle East, where the stakes for the U.S. and Russia are also high.

The strategic Black Sea peninsula of Crimea — now the flashpoint for a new crisis in Ukraine. Russian troops took control of Crimea after Moscow-backed Ukrainian president Viktor Yanukovych fled the capital Kiev. The move in Crimea has inflamed tensions between Moscow, and the U.S. and its European allies. Moscow maintains the military forces in Crimea are locals, not Russians. But President Vladimir Putin insisted his government reserves the right to use force to protect ethnic Russians throughout Ukraine

Russian President Vladimir Putin: “If we see that lawlessness starting in Eastern regions too, if people ask us for help — and we have already an official address from the current legitimate president — we reserve the right to use all options at our disposal to protect those citizens.”