An estimated 70,000 Russian troops have been gathered along their country's western border with Ukraine.
This is a divided nation.
Some Ukrainians want their country to be more involved with the European Union, others want closer alignment with Russia.
Ukrainian President Volodymyr Zelensky believes a coup maybe in the works.
That a Ukrainian businessman who's an ally of Russia may try to take over Ukraine, and that the Russian troops stand ready at the border to help.
That businessman and the nation of Russia has repeatedly denied that, but Russia does support forces in Ukraine that are fighting for independence from their government.
And Russia did annex, or take over, a Ukrainian peninsula in 2014, after people there voted to become part of Russia.
Other countries said the vote wasn't fair and that the Russian takeover was illegal.
The United States was one of those countries.
It's Obama Administration imposed sanctions or penalties on Russia for this, but critics said those penalties were too weak.
U.S. President Joe Biden said they'd be stronger this time, if Russia invades Ukraine but his administration says it won't send American troops into a possible conflict.
Why might Russia want to invade Ukraine anyway?
Well, it's concerned that other European countries, with the support of the United States, could be moving weapons and defense equipment closer to Russia's border.
It does not want that happening in Ukraine, a Russian-Ukrainian alliance could help prevent that.
U.S. President Biden and Russian President Vladimir Putin spoke about all this on a call this week. The diplomacy is delicate.
A high stakes call amid fears of a Russian invasion.
Hello. Good to see you again.
With tensions simmering on the border of Ukraine, President Biden spoke to Russian President Vladimir Putin for two hours and one minute.
The call covered a range of issues but the main topic was Ukraine.
The call [was] posing a critical test for Biden as he tries to avoid a major European security crisis if Russia invades Ukraine.
So, did President Biden get clarity from him on whether or not that is his intention?
We still do not believe that President Putin has made a decision.
What President Biden did today was lay out very clearly the consequences if he chooses to move.
Biden warning Putin about strong economic consequences and quote, "other measures" but it remains to be seen if the combative Russian leader backs down.
There was no finger wagging, but the president was crystal clear --
Putin had his own demands, including blocking Ukraine from joining the military alliance known as NATO.
He made no such commitments or concessions
--Sullivan adding that the U.S. is prepared to act in ways it didn't after Russia illegally annexed Crimea when President Obama was in office.
I will look you in the eye and tell you, as President Biden looked President Putin in the eye and told him today that things we did not do in 2014.
We are prepared to do now.
Tensions between the United States and Russia have only gotten worse in the months since Biden and Putin sat down for talks in Geneva.
At that meeting in June six months ago, Biden predicted he would know soon if he had made real progress with Putin.