Greek Prime Minister Alexis Tsipras is calling a vote of confidence in his government.
That's after his coalition ally quit on Sunday (January 13) - leaving Tsipras short of a parliamentary majority and raising the possibility of snap elections.
Panos Kammenos resigned his post as defense minister and said he was taking six other cabinet ministers with him.
It was a move of protest against a deal agreed last year to end a long-running dispute with neighboring Macedonia over its name.
Greece has a province called Macedonia and has long demanded Skopje change the country's name.
Last year they agreed to a new one - North Macedonia.
That accord was required for the tiny Balkan nation to join the European Union and NATO, but it still needs to be ratified by the Greek parliament.
And that's where Macedonia runs into the same mathematical problem Tsipras is now facing.
His Syriza party has 145 seats in Greece's 300-member parliament.
Kammenos's Independent Greeks provided an extra seven lawmakers to get Tsipras across the 150-seat threshold.
But Kammenos has now taken them away.
He says that any deal with Greece's northern neighbor including "Macedonia" in the name is unacceptable - as it is irrevocably tied to Greek civilization and culture.
Greece is already meant to hold elections in October, though that could be brought forward depending on the outcome of the confidence vote.
Pre-election polls suggest Syriza is trailing between eight and 12 points behind the main conservative New Democracy party, which opposed the deal with Macedonia.
On Sunday's (January 13) Greece parliamentary speaker proposed January 16 for the confidence vote.