In the event, the swing against the Republicans and the Bush administration in Tuesday's US midterm elections was decisive, nationwide - and very well judged. It is a welcome political change which gives the Democrats control of the House of Representatives and probably of the Senate as well.
President Bush read the signals quickly by accepting Donald Rumsfeld's resignation yesterday, indicating he understands clearly how central the Iraq issue was for American voters. By saying he will now consult party leaders on the best way to proceed there, he may also be hinting that the best means of securing his own political legacy is through co-operation with the new congressional majority.
Both in domestic and foreign policy this would represent a major departure from the partisanship and unilateralism of the last six years. Mr Bush was able systematically to play to his base over that time because of loyal and often unquestioning support from the Republican Congress. That is bound to change now. Mr Bush must decide whether to go along with this or to retreat into a defensive and increasingly lame duck mode for the next two years.
He has considerable political experience of bipartisanship from his time as governor of Texas. And it is not difficult to identify policies such as immigration reform, Iraq or climate change on which there could be fruitful progress made. It would have to be combined with demands that Mr Bush be made more accountable, along with a realistic understanding by the new Democratic majority that he retains ultimate executive power.
Although this is a decisive shift in the US political mood, it is also a complex one. The ingredients of the new Democratic majority are many and varied. The party benefited from sharp swings by independent voters and from Hispanics and saw a return to their old allegiance by conservative blue collar and some middle class voters who deserted the Democrats during the Reagan years and remained alienated under President Clinton. On this occasion they have shifted against a poor administration; it is too soon to say a major realignment in US politics is thereby heralded.
The Democrats are a more diverse party now, notwithstanding the greater discipline which gave them this victory. Their domestic programme calls for a minimum wage, income boosts for middle earners and greater attention to their social security. Beyond this, there is vagueness and lack of definition, especially on attitudes to free trade and protectionism - and the ambiguity extends across party lines. It is therefore difficult to read the new US mood on these issues. Europeans should not assume it will be more accommodating across the board. But they are entitled to expect a more open and multilateral approach towards Iraq and the Middle East and on world climate change. It will take some time before these results affect US policies.