, and trying to unseat him, don't agree on much. But when it comes to the immigration crisis on the border, both have introduced bills that do almost the same thing: They want to prohibit U.S. authorities from separating children from parents who are charged with crossing the U.S.-Mexico border illegally.
Their state of Texas features about 1,250 miles of border with Mexico and has become ground zero for questions about whether the White House's immigration crackdown has gone too far. Even though President Donald Trump reversed course last week with an executive order, it poses an election-year question. Could the continued fallout hurt Cruz enough to make him vulnerable, setting up a monster November upset that could potentially flip control of the Senate?
The Trump administration two months ago unveiled a "zero tolerance" policy which led to immigrant parents being separated from their children after crossing illegally into the U.S. and sparked weeks of criticism from Democrats and even many Republicans. Amid increasing public outcry, the president's executive order aimed to end that practice.
But 2,000-plus kids remain separated from their parents in federal custody, while confusion along the border about how to handle families that have crossed since has further increased tension and desperation. A judge in California now has ordered authorities to reunite separated families within 30 days, setting a fixed deadline that could be hard to meet.
Lawmakers are trying to hammer out legislation to address family separations, but getting anything passed will require Democrats and Republicans to work together, a challenge that is proving especially difficult with midterm election season now heating up.
WHY IT MATTERS
Trump got elected promising to wall off America's entire southern border. His hardline immigration policies are popular with the party's conservative base, especially in Texas, where Democrats haven't won a statewide office since 1994.
But sounds of wailing toddlers separated from their parents and images of children held alone behind metal caging proved too much for Cruz and many in his party. Democrats like O'Rourke, meanwhile, have flocked to Texas to tour detention facilities, decry what they see and attempt to keep the border in the news, figuring it will hurt the GOP in November.
If Congress fails to reach an agreement, though, the backlash could hurt both parties as the chaos both sides claim to oppose continues on the border.
WHAT TO WATCH
How, and especially when, will the thousands of immigrant parents and children still separated be reunited? What does Trump's executive order mean in the long term for families? Could the order ultimately be suspended amid challenges filed in federal court, creating still more questions about border enforcement?
Will congressional Republicans and Democrats finally reach some consensus on immigration? If so or if not, can either side use the issue to seize momentum heading into the midterms, and will voters be swayed by the outcome enough to buoy candidates around the country that look like longshots, including O'Rourke?
Thirty-nine percent of Texas' 28-plus million residents are Hispanic, the nation's largest Hispanic population behind California. But only about 38 percent are eligible to vote.
Around 40.5 percent of eligible Hispanics statewide cast ballots in 2016, compared to nearly 63 percent of Texas whites. That's a key reason why Democratic dreams that demographics will one day soon turn fiercely red Texas blue remain unrealized.
Ironically, O'Rourke, white and of Irish descent, grew up on the border in El Paso and speaks fluent Spanish, while Cruz, whose father immigrated to Texas from Cuba shortly after Fidel Castro took power in 1959, has only minimal skills en espanol.