Dutch Labor Party leader Lodewijk Asscher refused to shake hands with his Green party counterpart, Jesse Klaver, on Friday and agree not to go into government again with the right.

In an election debate broadcast on Dutch public radio, Klaver asked Asscher to commit to a progressive alliance and not join another coalition with the center-right liberal party.

Asscher refused to make that promise, calling Klaver’s suggestion “a little arrogant”.

Polls do not suggest the left will win a majority next month. Incumbent prime minister Mark Rutte’s liberals will almost certainly be needed to form the next government.

Disappointed

Many left-wing voters are disappointed that Labor teamed up with Rutte’s liberals after the 2012 election, even though parties in the center blocked a left-wing alternative at the time.

Labor did get important concessions from the right: liberalizations in health care were suspended and new rules for contractors introduced.

But the party also accepted spending cuts, in order to keep the Netherlands’ shortfall under the European 3-percent ceiling, and an increase in the retirement age from 65 to 67.

Coalition politics

The Greens and far-left Socialists accuse Labor of selling out its principles. They are now polling at a combined 20 percent support against 8 percent for Labor — an historic low for the once-dominant social democrats.

Yet Klaver’s pledge could come back to bite him.

Unless there are huge shifts in the polls between now and election day, it looks like the next coalition government will consist of Rutte’s liberals, the more centrist liberal Democrats, the Christian Democrats and at least one party from the left. The Greens could have a chance to govern nationally for the first time in their history, but that would mean going back on Klaver’s word.

He may end up disappointing left-wing voters the same way Labor did five years ago.