While Dewhurst outpaced Cruz by a healthy margin on Tuesday, the runoff could prove more challenging. With two more months to raise his name recognition and chip away at the frontrunner's lead, Cruz could capitalize on what is expected to be a low-turnout late summer election. On the other hand, Dewhurst has demonstrated a willingness to tap into his personal wealth, and he will likely outspend Cruz by a wide margin over the next two months.
Like Dewhurst, Leppert spent millions of his own money on his campaign, but he failed to catch on with Republican voters outside of Dallas. His presence in the race may have kept Dewhurst under 50 percent, though. Meanwhile, former ESPN college football analyst Craig James earned just 4 percent of the vote.
The eventual Republican nominee will face the winner of a Democratic runoff between former state Rep. Paul Sadler and the second-place finisher -- either retired teacher Grady Yarbrough or Homeland Security disaster assistance worker Addie Allen. With 37 percent of precincts reporting, Sadler led Yarbrough 35 percent to 26 percent, followed by Allen with 23 percent.
Republicans are expected to easily hold onto the seat being vacated by retiring GOP Sen. Kay Bailey Hutchison.