BRUSSELS - Deep divisions over how to cope with a flood of migrants from the Middle East, Africa and Asia pose a threat to the European Union's values and global standing and may diminish its ability to act jointly to reform the euro zone and ease Greece's debt.
With harrowing images of drowning children, refugees being herded on and off trains and beaten by police, and barbed-wire fences slicing across Europe, the migration crisis is the moral equivalent of the euro zone crisis. In both cases, the principle of solidarity is being sorely tested.
By making the EU look ineffective, disunited and heartless, pitting member states against each other and fuelling political populism and anti-Muslim sentiment, the latest crisis is undermining the ideals of European integration.
However, it often takes a bout of disarray and recrimination before the EU finds a joint response to a new challenge. Policy may be shifting in reaction to unbearable pictures of suffering, and to fears that the Schengen zone of open-border travel among 26 continental European countries may otherwise fall apart.
"The world is watching us," German Chancellor Angela Merkel said last week as she tried to persuade European peers to share the burden of taking in people fleeing war and misery in Syria, Iraq, Afghanistan, Libya and beyond.
"If Europe fails on the refugee question, its tight bond with universal human rights will be destroyed, and it will no longer be the Europe we dreamed of," she said.
Merkel's bold attempt to exercise leadership, in contrast to her deep caution in the euro crisis, has won only cautious support from close allies like France, where domestic opposition to more immigration is strong, and been rejected outright by countries such as Hungary and Britain.
For many European politicians trying to keep in tune with voters, preventing unwanted immigration is a greater priority than welcoming hundreds of thousands of haggard, uprooted foreigners, especially if they are Muslims.