KIEV, Ukraine — While thousands of demonstrators call for ousting Ukraine’s leaders, Yuri Onishchenko is also worrying about matters more pedestrian, such as where to find wool socks to help the demonstrators keep warm in snowy December weather.

As the acting head of the sizeable protest tent camp in Kiev’s central square, Onishchenko takes the lead in making sure the demonstrators have what they need to keep the flame of their passions burning.