Mexico City ? Opposition legislators sprawled across the congressional speaker’s platform in their standoff with ruling conservatives Wednesday, vowing not to budge in hopes of blocking Friday’s inauguration of President-elect Felipe Calderon.

Lawmakers representing the rival factions stormed the platform in Congress on Tuesday, and have occasionally shouted, pushed and thrown punches near the podium where President Vicente Fox is supposed to hand power to Calderon.

On Wednesday they lounged on the stage reading papers and talking on their cell phones, leaving in shifts to take showers.

The opposition Democratic Revolution Party claims its candidate, Andres Manuel Lopez Obrador, was cheated of victory by vote fraud in the July 2 presidential election. Party lawmakers hope to disrupt Calderon’s inauguration ceremony, and ultimately prevent him from taking office.

The Mexican constitution says that presidents must be sworn in before Congress, but experts disagree over what that means. Some say it requires a majority of members of Congress to be present, while others say the congressional leader, Sen. Jorge Zermeno of Calderon’s conservative National Action Party, could perform the ceremony himself.

Sen. Manlio Fabio Beltrones, a leader of the Institutional Revolutionary Party, suggested holding the ceremony elsewhere. Most Mexican presidents of the 20th century were sworn in at large theaters or stadiums rather than the building that houses Mexico’s Congress.

Fox and others have argued that Calderon will become president Friday with or without an inaugural ceremony.

But Sen. Raymundo Cardenas of the Democratic Revolution Party said his party would try to prevent Calderon’s swearing in, and in any case will not accept him as president.

“We’re never going to recognize Felipe Calderon as president,” he said. “If he isn’t sworn in … he isn’t president.”