Sept. 1 (Bloomberg) -- Mexican President Vicente Fox canceled his final State of the Union address after opposition legislators occupied the podium where he would speak to protest what they say was state-sponsored fraud in the presidential election.

Legislators who support Andres Manuel Lopez Obrador, the second-place finisher, held signs calling Fox a ``traitor to democracy'' and shouted ``ballot by ballot'' to demand a recount of the July 2 vote. A federal court this week dismissed most of Lopez Obrador's claims and will issue a final ruling next week.

``Given the attitude of a group of legislators that make it impossible for me to read the message I had prepared for this occasion, I am leaving,'' Fox said, minutes after he arrived in the Congress in Mexico City.

The obstruction of the State of the Union address for the first time in Mexico's history represents a radicalization of Lopez Obrador's party that will erode support for their protests, said Armand Peschard-Sverdru from the Center for Strategic and International Studies.

``President Fox wins and Lopez Obrador and the left lose,'' Peschard-Sverdru, director of the Mexico Project at the center, said in a telephone interview from Washington.

Lopez Obrador, 52, says Fox conspired with business groups to illegally campaign for governing party candidate Felipe Calderon. Presidential spokesman Ruben Aguilar dismissed Lopez Obrador's allegations in an Aug. 21 news conference, saying: ``He who accuses has to prove.'' The electoral court will rule on the allegations and the validity of the election by Sept. 6.

Ballot Count

On July 6, election authorities finished a count of voter ballots showing that Calderon, 44, won by 243,934 of the 40.9 million valid votes cast.

``We've showed the world the political situation that is taking place in Mexico,'' said Miguel Angel Solaris, federal deputy from Lopez Obrador's party as he occupied the stage in the congress.

Lopez Obrador, who drew about 1 million people in two of three rallies in Mexico City, today canceled plans to march to the Congress after Mexico City police placed 12-foot-tall metal barriers up to one mile from Congress, set up checkpoints and deployed water cannons to disperse protests.

The former Mexico City mayor urged supporters to keep protests peaceful.

``We must not fall in their trap,'' he told thousands on supporters gathered in the capital city's main square. ``We're in the right. People who use brute force do it because they aren't in the right.''

Lopez Obrador has called for another rally in the Zocalo on Sept. 16, the same day the army is scheduled to occupy the square for its annual Independence Day parade. He will ask his supporters during the meeting to define his role as either head of an ongoing civil resistance movement or as a ``legitimate president'' elected by the will of the people.

To contact the reporter on this story: Patrick Harrington in Mexico City at pharrington8@bloomberg.net

Last Updated: September 1, 2006 22:13 EDT