German chancellor Angela Merkel is facing the first electoral test of her refugee policy

just as the pillars of the EU's response come under sustained assaults.

EU leaders are preparing for an emergency migration summit on Monday against the grim backdrop.

Desperate scenes of the Greece-Macedonia border

where crowds of migrants are being beaten back from storming a fence with salvos of tear gas

Four crucial components of Europe's migration response are at stake.

Ms. Merkel is beset on all sides domestically and isolated abroad.

Her personal popularity still remains relatively high

but the arrival of 1.1 million refugees in Germany has dented her command of German politics.

Her CDU party is bracing itself for a poor showing in three state elections scheduled for March 13

that have turned into a referendum on the chancellor's refugee strategy.

She insists there is no Plan B,

but if two EU summits this month failed to deliver results, a stricter approach may be inevitable.

Turkey is a center piece of the EU's migration strategy.

Here at three months after the EU-Turkey deal to cut migrant flows,

more than 2000 people today are still making the Aegean crossing.

There is now a deadlock.

Ankara will not act more decisively until the EU starts taking in refugees directly from Turkey

had the EU wants numbers dramatically down before it will consider resettlement.

Diplomats are in despair, but one hard fact remains.

Neither Berlin nor Athens can cope, either politically or practically,

with another 1 million arrivals in 2016.

Up to 70 thousand refugees are forecast to be stuck in Greece in coming weeks.

There are serious concerns of a humanitarian crisis.

Ms. Merkel is worried.

Greece is in a fragile state politically and economically.

"We didn't keep Greece in the euro only to then leave it in the lurch," she said on Sunday.

The EU's flagship policy of relocating refugees in Italy and Greece has resulted in roughly 600 people out of a proposed 160,000 actually moving.

Worse still, countries are beginning to act alone to tighten borders

ignoring objections from Berlin and Brussels.

EU officials are frantically searching for ways to revive a common refugee policy

but it faces huge political obstacles.

One eurozone minister told us

"We're close to our worst nightmare, a negative spiral of closed borders and independent policies.

I don't want to go there, but we don't have long."

Alex Barker, Financial Times, Brussels.