Ukraine is set to hold presidential elections this Sunday. Some observers say the vote is the most important in Ukraine since it became independent from the Soviet Union in 1991. The voting comes two months after Russia's takeover of the Crimean peninsula from Ukraine. Since then, separatists in eastern Ukraine have declared their independence from the central government. And security forces have clashed with separatists in a number of eastern cities.
The events in Ukraine are being closely watched in Europe and around the world. The unrest has affected efforts by the United States to persuade other countries to change their policies.
U.S. officials travel the world to build support on a number of issues, from the civil war in Syria to Iran's nuclear program. But some observers believe the West's reaction to the Russian moves in Ukraine has harmed those efforts.
Ukrainian presidential candidate Petro Poroshenko meets with supporters in Uman, Cherkasy region, May 20, 2014.
Olexiy Haran teaches comparative politics at the National University of Kyiv-Mohyla Academy.
"How are you going to persuade other nuclear states like Iran, North Korea, to give up their nuclear weapons, in exchange for what? They see that, in Ukraine, these guarantees didn't work."
Professor Haran notes that Russia was seen as a guarantor of Ukraine's independence but then took control of Crimea.
"We expect a strong reaction from (the) international community because it undermines the whole system of security which is in Europe now."
The Russian military has been active along the border with Ukraine. But Western nations have reacted with "soft power" – diplomacy and economic actions. Around the world, that was seen as weak, says Xenia Dormandy. She is a U.S. policy expert with Chatham House in London.
"That's a very, very dangerous message to take away because each situation is different. That's how you get people crossing red lines, because of that ambiguity, and you have potential conflict."
Still, she thinks the soft power response is not as weak as it might seem.
"Absolutely not! The response will, in time, have significant effects on the Russian economy."
Some of those effects are already being felt. Russian President Vladimir Putin has started to distance himself from militants in eastern Ukraine, at least officially.
However, observers agree the Russian takeover of Crimea cannot be undone. And they say the danger still exists of a Russian invasion of eastern Ukraine.
So if other countries are looking for lessons learned in the Ukraine crisis, it may be too early to know what they are.
I'm Anna Matteo.