On February 11, 2010, U.S. Rep. Lincoln Diaz-Balart (R-21st Congressional District) announced that he would not seek election to a 10th term in Congress this fall. His younger brother, U.S. Rep. Mario Diaz-Balart (R-25th Congressional District) immediately announced that he would run for the 21st Congressional District seat. The 21st District, which is thought to be more safely Republican than the 25th District, includes parts of Miami-Dade and Broward counties. The 25th District includes the western portions of Miami-Dade County, all of Monroe County, and most of Collier County.

The open 25th Congressional District seat may affect state campaigns. State Rep. David Rivera (R-Miami) has told reporters that he is “seriously considering” running for the seat. Rep. Rivera is currently running in a highly competitive Republican primary for the state senate seat being vacated by term-limited Sen. J. Alex Villalobos (R-Miami). Rep. Rivera raised $1,031,103 for his state senate race through the end of 2009, more than any other candidate for the state Legislature; his primary opponent, Rep. Anitere Flores (R-Miami) raised $390,280.

Term-limited Sen. Alex Diaz de la Portilla (R-Miami) said in a statement that he is “seriously considering” running for Congress. Newspaper accounts have mentioned several other potential Republican primary candidates, including Sen. Villalobos and Miami-Dade County Commissioner Bruno Barreiro.