Biden says Romney "won't show us" his papers

(CBS News) LAS VEGAS -- Vice President Joe Biden on Tuesday went on the attack for the Obama campaign once again, telling Hispanic voters Mitt Romney wants to demand proof of their citizenship, but is secretive about his own finances.

"Mitt Romney wants you to show your papers, but he won't show us his," Biden said to thunderous applause during a keynote address to the National Council of La Raza Conference in Las Vegas. He was accompanied by his wife, Dr. Jill Biden, who introduced him as an advocate for the Hispanic community.

Biden drew the parallel between Romney showing only one year of tax returns - suggesting he is hiding something - to Hispanics showing proper documentation that they are American citizens.

"When his father, George Romney, was a candidate for President in 1968, he released 12 years of tax returns because, as he said, 'One year could be a fluke, perhaps done for show," Biden said. "That was his father. His son has released only one year of his tax returns, making a lie of the old adage, 'like father, like son.'"

Watch an excerpt of the vice president's remarks in the video to the left.

The Romney campaign has said the former Massachusetts Governor has released all of the necessary documents required by law. And one campaign surrogate went further today, saying the Obama campaign needs to "get over" the tax issue.

"Governor Romney has been very successful," Rep. Jason Chaffetz, R-Utah, said. "Get over it."

The vice president ended his speech to the room full of more than 1,800 Hispanics in a crescendo, advising, "Ladies and Gentlemen - don't miss this. This is your moment, this is the moment for your community.

Vice President Biden makes an awkward sex joke in the video to the left.

"Your population is too talented, too capable, too grounded, too proud, and too patriotic. More than 1.3 million Hispanics have served in our armed forces, more than 637 have died, more than 2,789 have been wounded," Biden continued, building to the top of his lungs. "Don't tell me you're not ready."