A Houston lawyer and immigration activist has announced she will challenge incumbent John Cornyn, the powerful Republican Texas senator in next year's Republican primary.

Linda Vega, founder of a private Houston law firm, says a centerpiece of her campaign will be overhauling America's immigration system. Vega, who has worked for the U.S. Department of Labor, faces an uphill battle in the race.

Cornyn has been in office since 2002 and had for months avoided a credible conservative challenger for the March GOP primary.

Meanwhile, no Democrat has yet announced for Senate for the November 2014 general election. No Democrat has won statewide office in Texas in two decades.

Cornyn's campaign raised $1.8 million in the third quarter, which ended Sept. 30.

It said Wednesday that ranks second among all GOP Senate incumbents -- and that Cornyn's $6.9 million in cash-on-hand is third-highest among all Senate candidates from both parties.

Cornyn campaign manager, Brendan Steinhauser, was quoted by Politico as saying that the senator welcomes Vega to the race.

“As the 2nd most conservative senator in America, Sen. Cornyn looks forward to discussing his record and welcomes Ms. Vega into the race,” he said, according to Politico.

The Associated Press contributed to this story.