Republican Gabriela Saucedo Mercer says she's going to challenge Democratic Rep. Raúl Grijalva again for his 3rd Congressional District seat.
The political newcomer won 38 percent of the vote in November's general election to Grijalva's 58 percent.
Grijalva is serving his sixth two-year term and plans to seek re-election.
Saucedo Mercer said in a written statement released Tuesday that she believes 2014 is the year that Grijalva can be beaten.
The sprawling district borders Mexico in southwestern Arizona and includes the western half of Tucson, parts of Yuma and portions of several western Phoenix suburbs.
It has more than twice as many registered Democrats as registered Republicans, but about 34 percent of its voters are independents.