The Netherlands became the first NATO country to end its combat mission in Afghanistan, drawing the curtain Sunday on a four-year operation that was deeply unpopular at home and even brought down a Dutch government. The departure of the small force of nearly 1,900 Dutch troops is not expected to affect conditions on the ground. But it is politically significant because it comes at a time of rising casualties and growing doubts about the war in NATO capitals, even as allied troops are beginning what could be the decisive campaign of the war. Canada has announced it will withdraw its 2,700 troops in 2011 and Polish President Bronislaw Komorowski has promised to pull out his country's 2,600 soldiers the year after. That is likely to put pressure on other European governments such as Germany and Britain to scale back their forces, adding to the burden shouldered by the United States, which expects to have 100,000 troops here by the end of next month.