DRIPPING SPRINGS, Texas -- The race to replace Rep. Lamar Smith, R-San Antonio, is heating up on the Republican side with former Texas Governor Rick Perry throwing his support behind one of his former appointees Tuesday.

Congressional District 21 begins along I-35 from Austin to San Antonio and spans more than 100 miles west. With a total of 18 Republican candidates in the race, each one is doing what he or she can to attract attention.

State Rep. Jason Isaac, R-Dripping Springs, came up with the slogan, "Make America like Texas." Chip Roy, also of Dripping Springs, touted his endorsements by Sen. Ted Cruz, for whom he previously served as Chief of Staff, and Energy Secretary Rick Perry.

"Chip understands Texas, and he is a patriot and a man of conviction with a proven track record defending her people--whether it has been in my office, the Attorney General's office, or on Capitol Hill," Perry said.

"I was (Perry's) Director of State and Federal Relations," Roy said. "He saw me in the Attorney General's Office fighting to help sue against overreaching federal laws."

While Roy's served in government, he's never held elected office. He withdrew from a State House race in 2012, but Roy said he is ready for Washington.

"I think the first thing we need to do is to put the brakes on spending," he said.

Isaac, who touts a history of running against the GOP establishment and winning, echoed Roy's call to reduce the size of the federal government.

"You need to cut spending and taxes, and that gives people more freedom and makes government less important and part of our lives," Isaac said. When the Texas budget faced a shortfall, "the (state) government put a hiring freeze in place. If you actually wanted a job in a government agency, you had to get the governor's approval. That's something I support."

Others in the Republican Primary for District 21 include former Congressman Francisco Canseco and Bexar County Republican Party Chairman Robert Stovall. A full list of candidates for both the Republican and Democratic Primaries is below.