HOUSTON - US Vice President Joe Biden defended President Barack Obama's signature healthcare reform law in Houston on Thursday, in remarks to an NAACP convention, where Obama's Republican rival Mitt Romney got booed one day earlier for vowing to repeal the law.

US Vice-President Joe Biden speaks at the NAACP convention in Houston July 12, 2012. [Photo/Agencies]

The crowd at the annual meeting of the National Association for the Advancement of Colored People (NAACP) was receptive to Biden's speech, applauding heartily as he lauded Obama for his success in getting the law passed.

"This man prevailed where no president had before," Biden said. "And he was right, he was right."

One day after Romney was booed during an appearance at the NAACP's Houston meeting, Biden asked the audience to imagine what a conservative Romney presidency would mean for the Justice Department, the Supreme Court and voting rights.

"This is not your father's Republican Party," said Biden, who also condemned Republican support for voter ID laws that critics say will disenfranchise many black voters.

"Did you think we'd be fighting these battles again?" he asked the crowd. "When you have the right to vote, you have the right to change things."

Biden also defended Obama's performance in improving the country's economy. "He continues to be driven by the character of his convictions," the vice president said.

In his speech, Biden also touched on Obama's plan announced earlier this week to seek a temporary extension of tax cuts on income below $250,000.

Romney faced an uphill task politically in speaking before the NAACP, an African-American civil rights organization formed in the United States in 1909.

In 2008, Obama won 96 percent of the African-American votes on his way to become the country's first black president. Polls have shown black voters supporting Obama at comparable levels this year.