MIAMI (Reuters) - Republican U.S. Representative Lincoln Diaz-Balart, one of Congress' staunchest supporters of the U.S. trade embargo against Cuba, said on Thursday he would not seek re-election to his Florida congressional district.
Havana-born Diaz-Balart, 55, has represented a predominantly Hispanic district in the Miami area since 1993.
"Today, I am announcing that I will not seek a 10th term in the United States Congress this November," he told reporters in Miami. He said he planned to return to practicing law.
His brother, Republican U.S. Representative Mario Diaz-Balart, also holds a Florida congressional seat. He said on Thursday he would run in November for Lincoln's District 21 seat, which is considered more reliably Republican than the District 25 seat Mario currently holds.
All 435 seats in the Democrat-controlled House of Representatives will be up for grabs in November. There are now 18 House Republicans and 12 Democrats who have said they will not run for re-election.
The Diaz-Balart brothers and Cuban-born U.S. Representative Ileana Ros-Lehtinen of Florida have been a powerful force in support of a hard-line U.S. policy against the communist government in Cuba established by Fidel Castro after his 1959 nationalist revolution on the island.
Analysts of U.S.-Cuban relations said that because of Lincoln Diaz-Balart's seniority in the House, his absence from November would be felt among supporters of the embargo.
"His departure is significant in that he is stalwart and effective and he has seniority," said Phil Peters, a Cuba expert with the Lexington Institute in Virginia.
But analysts said Lincoln Diaz-Balart's announcement, and his brother's decision to run for the safer District 21 seat, also reflected a more moderating shift in the anti-communist Cuban exile community in recent years in favor of greater contacts with Cuba, as opposed to isolation.
"He understands that his base is changing and shifting," said Carlos Saladrigas, a Cuban American businessman in Miami who argues that the best way for Washington to bring political change to Cuba is to increase contacts and engagement.
"There are a significant amount of Cuban Americans who are voting with their feet," added Saladrigas, citing the increased numbers of Cuban exiles who have visited their homeland since U.S. President Barack Obama last year eased restrictions on Cuban-American family travel to the island.
The U.S. embargo, which currently prohibits all trade except for the non-subsidized sale of food and medicine, took effect in 1962, after Castro embraced communism and aligned himself with the Soviet Union.
Lincoln Diaz-Balart said one of his proudest achievements was helping write into law a provision that prevents U.S. presidents from lifting the embargo until Cuba frees all political prisoners, legalizes political parties and labor unions and schedules free multiparty elections.
"The reason why the world today debates the issue of Cuba, in contrast to the also condemnable internal situations in the other totalitarian states ... is because the U.S. embargo exists, and will continue to exist until those three fundamental conditions are met," he said.
The aunt of Lincoln Diaz-Balart is Mirta Diaz-Balart, Castro's ex-wife.
Debate over the U.S. embargo's effectiveness increased after Castro stepped down as Cuban president in 2008. He was replaced by his brother Raul Castro, who has largely maintained his brother's policies to preserve Cuba's communist system.
Lincoln Diaz-Balart said he would work to support Cuban political prisoners, without specifying how.
"I am convinced that in the upcoming chapter of the struggle, I can be more useful to the inevitable change that will soon come to Cuba, to Cuba's freedom, as a private citizen dedicated to helping the heroes within Cuba ..." he said.
Ros-Lehtinen praised his work on behalf of immigrants and called his departure a sad day for south Florida, which has the United States' largest concentration of Cuban exiles.
"We have lost a tireless fighter for a free and democratic Cuba and a savvy and keen parliamentarian who was a great leader in the Rules Committee, one of the most powerful committees in Congress," she said.
Additional reporting by Tom Ferraro and Pascal Fletcher; Editing by Eric Beech