But others within the administration, and many outside experts, are increasingly worried that if President Obama does not take decisive action — such as quickly moving to claim the airspace over northwestern Syria and the Turkish border, where Russian jets are already operating — it is the United States that will suffer significant damage to both its reputation and its foreign policy and counterterrorism goals. Putin has said he does not intend to launch military ground operations in Syria, and senior administration officials said Wednesday that they see no evidence of any ground combat units there. But the Russian deployments include sophisticated electronics, some of them designed to jam aviation electronics. Other than Russia and the Syrian government, only the U.S.-led coalition against the Islamic State is flying planes in Syria.