Greece's lenders, especially the IMF, want the Greek parliament to adopt a €3.6 billion package of austerity measures that would be implemented only if Greece missed its primary surplus target for 2018, set at 3.5 percent of GDP by the bailout memorandum signed last year.
The primary surplus is the budget surplus before the state has to repay interests on its debt.
The Greek government, which said legislating in advance was unconstitutional, has proposed to commit to take measures in the future if fiscal data approved by Eurostat show that the target will be missed. A more political argument is that the quartet's request for a contingency package goes beyond what was agreed by eurozone leaders last July and then written down in the bailout memorandum of understanding signed in August. That is why Tsipras, who always said he would do "nothing more and nothing less" than what was agreed last summer, is trying to push the discussion back to the highest political level. A eurozone summit is however unlikely, as EU leaders have been willing to let their finance ministers deal with the Greek crisis. The leaders took over the talks last year only when a Greek exit from the eurozone became a real danger.