The simple act of walking has become a display of defiance for a young Iranian woman who often moves in Tehran's streets without a compulsory headscarf, or hijab. With every step, she risks harassment or even arrest by Iran's morality police whose job is to enforce the strict dress code imposed after the 1979 Islamic Revolution. The hijab debate has further polarized Iranians at a time when the country is buckling under unprecedented U.S. sanctions imposed since the Trump administration pulled out of a 2015 nuclear deal between Iran and world powers last year.