With early voting starting Monday, this is what you need to know. Texas has open primaries, meaning you don't have to be a registered member of either party to cast a ballot in a primary runoff. Those who did not participate in the March primary are able to vote in either primary runoff election. Abbott also doubled the length of the early voting period for the July primary runoff elections in a move to aimed at easing crowds at the polls during the pandemic. Early voting runs from Monday through July 10.