Election day for the Texas primaries is in less than a week, and the race for a representative spot in Texas’ 21st Congressional District is heating up.

The 21st District covers a substantial part of South Austin and most of West Campus, and with 18 Republicans seeking the seat of retiring incumbent U.S. Rep. Lamar Smith, R-San Antonio, it could be anyone’s race.

“UT students getting involved and figuring out which one of these candidates is speaking to them could mean all the difference in the world in who makes it to the run-off,” Sean Theriault, government professor who specializes in Congress, said. “When there are 18 (Republican) candidates running, 200 votes could be the difference between second and sixth place.”

Smith is retiring this session after a 32-year run, leaving a sea of Republicans and four Democrats to fight for his spot. While Theriault said competition for the seat makes sense given the potential for another long career like Smith’s, the number of Republican candidates in the running is still abnormal.

“You don’t usually see this many people,” Theriault said. “Usually there is a handful, and what happens is when there is an opening like this, one or two people with lots of notoriety get in, and so they scare everyone else out. I think when those people didn’t emerge, then everyone … kind of threw their hats in the ring.”

While there is not yet a clear front-runner from either party, some candidates are more recognizable than others. State Rep. Jason Isaac, R-Dripping Springs, Chip Roy, former chief of staff for U.S. Sen. Ted Cruz, former Bexar County GOP chairman Robert Stovall and former U.S. Rep. Francisco “Quico” Canseco are strong contenders, on the Republican side. Some unfamiliar faces stand out in the race as well, such as William Negley, a former CIA agent who refers to himself as a “terrorist hunter” on his yard signs and is backed by billionaire Red McCombs, according to The Texas Tribune.

Theriault said the four Democrats running, including businessman Joseph Kopser and former congressional staffer Derrick Crowe, may also have a chance to take the seat in November, given demographic changes happening in Austin.

“There are other seats in Texas that are more likely to slip to the Democrats before this one,” Theriault said. “But without an incumbent running, and with the Republican field as wide open as it is, the Democrats certainly have a better shot than they’ve had in many years in this part of the state.”

With the Republican vote split between so many candidates, Theriault said there will almost certainly be a runoff election, which will occur in May if one candidate does not receive more than half of the primary vote. He said with so many variables thrown into the mix, only time will tell how the race will shape up.

“It’s really hard to figure out who’s going to rise to the top,” Theriault said. “My suspicion is the winning (Republican) candidate in the primaries is going to get about 20 percent of the vote, but I’m sure that there are about 10 of those folks who think they are going to 20 percent of the vote. It’s going to be fascinating to see what actually happens when the vote comes down.”