While the political implications of a runoff are debated, there's one aspect of the race that seems clear: The money will continue to flow into Texas until the party has a nominee.
"I think it's inevitable that spending will increase if there's a runoff," said Cruz.
Spending has already exceeded $25 million, according to the Center for Responsive Politics, making it the most expensive U.S. Senate race so far this cycle.
The sheer geography of the Lone Star State makes it an extremely expensive place to campaign. Texas is simply too big for a candidate to feasibly reach every part of it without taking to the airwaves, and Texas media markets are costly.
Both sides report raising around $6 million. Dewhurst has sunk a portion of his own fortune into the race, too, spending a total of $8 million of his own money in his Senate bid, according to campaign disclosures.
The candidate who ultimately wins the primary in this solidly red state is widely expected to win the Senate race in the fall.