Early rounds fired in sanctions war against Russia
All sanctions are intended to persuade, to change minds and to raise the cost of courses of action.
President Putin and his close circle will on Monday have been watching Brussels and Washington, trying to decipher their determination to hurt Russia over its actions in Crimea.
The acid test is whether the steps of the West carry conviction and reflect resolve.
EU foreign ministers have taken a cautious, modest step.
Putin's 'inner circle'
Twenty-one Russians and Ukrainians have been targeted for asset-freezes and travel bans.
Crimean parliament formally applies to join Russia
The EU going forward will have to review whether it is too dependent on Russia for energy. Whether EU officials realised it or not they have got drawn into a much bigger and more dangerous game than pressing for enlargement.
So, this week the challenge for the EU must be to show resolve and unity. Any divisions will be exploited by Russia. Resolve will be to deliver on consequences warned about.
Ukraine: Europe’s major test
The week ahead will test Europe's resolve and its ability to act over Ukraine.
One senior official in Brussels said: "It is going to be a major test of European unity post-Cold War."
Ukraine crisis: Europe's leaders respond to Russia
Events have stripped Europe's leaders of their illusions. They are gathering in Brussels for an emergency summit on Ukraine in a sombre mood.
The heady rhetoric of European officials declaring "the future of Ukraine belongs with the EU" has long been discarded. The image of protesters waving EU flags has faded. The understanding of the protests, which included nationalist groups, is far more nuanced.
Ukraine: How will the West respond?
I had been absent from Kiev for less than three days. The lightness, the hint of a Kiev spring, the sudden smiles of a week before were already waning. Now the mood is much darker; there is defiance and rage against Moscow and Russia's President Vladimir Putin.
Just seven days earlier some had dared to speak of "victory"; now the talk is of war. Speaking of Russia's actions in Crimea, the new Prime Minister Arseniy Yatsenyuk said "this is the red alert, this is not a threat, this is actually a declaration of war".
Ukraine's dangerous days ahead
On Tuesday the crowds were still filing into Kiev's Independence Square and the surrounding streets where most of the killings took place. Many of them carried flowers to place at the scores of shrines.
They were a quiet, serious, absorbed crowd. There was no hint of celebration or victory. A mother took a picture of her two young daughters as they added to the piles of flowers.