Sen. Ted Cruz (R-TX) turns toward Rep. Beto O'Rourke (D-TX) to make a point during a debate at McFarlin Auditorium at SMU. Tom Fox-Pool/Getty Images

With two days remaining until the midterm election, one of the most contentious races remains tight, but still in favor of the incumbent. Republican Sen. Ted Cruz leads in all polls over Democratic challenger Robert "Beto" O'Rourke in the Texas U.S. Senate race.

According to polls compiled by, Cruz has led in all 21 polls conducted since April. No poll has even been a tie. A recent survey by CBS 11 and Dixie Strategies had Cruz up by 11 percent. In late May, a Quinnipiac University poll, considered among the most reliable, had Cruz up by 10 points.

However, the latest poll, conducted by Emerson College, shows Cruz with an advantage of just 3 points and within the margin of error. The poll lists Cruz at 50 percent, O'Rourke at 47 percent and with 2 percent undecided.

More encouraging for O'Rourke is that Change Research has O'Rourke and Cruz even at 49 percent, while Libertarian Neil Dikeman is at 1 percent. On its Twitter account, Change Research notes: "We've polled a lot in Texas the past few months, and this marks a notable shift towards Beto."

A victory for O'Rourke would be a massive upset for Democrats looking to gain control of the Senate. The last time a Democrat was elected to the U.S. Senate from Texas was Lloyd Bentsen's landslide victory in 1988. Democrats haven't won a statewide race since 1994.

O'Rourke is hoping for a strong voter turnout, particularly from Latinos. The El Paso congressman has drawn massive crowds throughout the race, while campaigning in every Texas county. Texas, however, has historically had dismal voter turnout in most election cycles.

Cruz, who is seeking his second term, easily defeated his 2012 Democratic opponent, Paul Sadler, 56.46 percent to 40.62 percent.