Defense Secretary Robert Gates said the pace of a planned US troop drawdown in Afghanistan next year would be based mainly on conditions on the battlefield rather than "domestic politics" in the United States. Republican lawmakers, who won control of the House of Representatives in US legislative elections on Tuesday, have made clear they oppose a July 2011 target date for the start of a gradual withdrawal from Afghanistan, warning they will press their case when the new Congress convenes in January. Speaking to reporters aboard his plane before landing in Melbourne for annual security talks with Australia, Gates said the effect of the mid-term elections on the withdrawal plan "remains to be seen. ""Partly I think things will depend on our assessment next spring and early summer of how we're doing. I think that will have the biggest impact on the president's decisions in terms of the pacing" of a troop drawdown, Gates said. The administration had always stressed that any reduction in troop levels would be determined by conditions on the ground, he said. "It will be based more on that than ... domestic politics," he said. The United States has about 100,000 troops in Afghanistan, serving along with some 50,000 non-US coalition forces.President Barack Obama ordered in 30,000 reinforcements to Afghanistan last year in a bid to turn around the war, but also vowed to start pulling out troops by mid-2011.Senior Republicans strongly oppose the deadline, saying it plays into the hands of the Taliban insurgency.