President Joe Biden is placing Kamala Harris in charge of addressing the substantial uptick in migrants, including unaccompanied children, flocking to the U.S.-Mexico border, handing a major political risk to his vice president.

As vice president, Biden was dispatched by then-President Barack Obama to address an increase in the arrival of Central American children at the U.S.-Mexico border — or what Biden at the time called a “dangerous surge of migration.”