Beware the ides of September, which promises to be a critical month for the future of Europe and the euro.

The key date is Sept. 13, by which the results of both the Dutch elections and the keenly awaited verdict of the German Bundesverfassungsgericht, the country's constitutional court, on whether the planned euro bailout mechanisms contravene the law, will be known.

The good news is that the Dutch opinion polls suggest that the anti-immigration and euroskeptic party of Gerd Wilders looks to be losing a lot of ground. The bad news in that formerly Maoist Socialist party is surging and may even become the largest party in Parliament. They aren't quite as euroskeptic but very populist, promising to maintain the generous Dutch welfare state and to oppose the austerity strategy being imposed on Europe by Germany.

The Socialists' track record dismays pro-Europeans, since they campaigned for a "No" vote in the last Dutch referendum on Europe. Now they demand a new referendum on the German-backed fiscal compact. which strictly limits budget deficits. They won't observe those limits, says Socialist leader Emile Roemer, 50, a former teacher.

The election is still two weeks away and much can happen in the course of the campaign. For the moment, it looks like the Dutch won't trigger an immediate crisis for the euro. But they seem likely to deliver (after testy and lengthy negotiations about coalitions) endless political arguments over European economic policy and to block German attempts to impose fiscal discipline.

Eight German judges, however, could provoke an immediate crisis Sept. 12 if they grant even a temporary injunction against the new $625 billion European Stability Mechanism. The key question for the constitutional court in Karlsruhe is whether the ESM undermines the prerogative of the German Parliament to be the sole body that can require German citizens to pay money to the state.

This isn't just about taxes but about fines and also about the power of European treaties to bind German taxpayers.

For example, under the ESM rules would the German Parliament be able to refuse additional multibillion-dollar contributions to the ESM if the $625 billion proves not to be enough and other countries cannot pay in? And if in future a Germany in recession cannot make its payments, would ESM rules punish Germany by suspending its voting rights?

These were questions that members of the court asked in June and government lawyers in Berlin have been scrambling to come up with answers that pass the constitutional smell test. If the court refuses to grant the injunction, a new problem emerges. That would mean that the government could go ahead and secure a parliamentary majority to ratify the treaty authorizing the ESM.

But would the German president sign the treaty? After all, a treaty once ratified becomes binding and what are the constitutional implications of that for the powers of the German Parliament?

Most German lawyers seem persuaded that the eight judges in Karlsruhe will find a way to let the government go ahead. But maybe they would attach provisos that could require the EU member states to re-negotiate the whole ESM treaty.

And while the German lawyers fiddle away, the eurozone's weaker members continue to burn.

The week before the court decision, the governing council of the European Central Bank meets in Frankfurt. This would normally be the occasion for any announcement on a change of interest rates and for ECB President Mario Draghi to spell out exactly what he meant last month when he calmed the markets by promising to do "whatever it takes" to save the euro.

But now everybody expects him to say nothing until the German court rules, which means the markets will focus on the meeting of the governing council and general council on Sept. 20. By then, the troika -- the ECB, the European Commission and the International Monetary Fund -- should have reported on whether Greece has fulfilled sufficient austerity conditions to qualify for the next tranche of European cash.

If the troika says "no," Greece would be bankrupt and could be forced out of the euro that week.

European leaders are trying to avoid that The likelihood is that somehow the show will be kept on the road, given that German Chancellor Angela Merkel has just launched a massive Ich Will Europa (I want Europe) propaganda campaign, which includes politicians, academics and German soccer star Philipp Lahm.

Europe has brought "peace, prosperity and understanding with our neighbors," Merkel declared in her own TV launch of the campaign. And she pledged that the crisis would result in a "sustainable and strengthened eurozone and European Union."

Will the Dutch go along? And what about the Finns, who now demand collateral for any new loans they make? And what will the Socialist-led French National Assembly do on Sept. 19, when they start to decide whether to ratify the new law on fiscal discipline and balanced budgets? That may depend on the new Dutch government.

The euro crisis is far from over. But in the course of September, it could assume a very different shape.