LAS VEGAS — Vice President Joe Biden denounced Republican presidential challenger Mitt Romney on Tuesday as a candidate with something to hide.

Biden, campaigning for President Barack Obama in the battleground of Nevada, told Hispanic leaders that Romney doesn't live up to the openness that his father represented when he ran for president 44 years ago. The vice president said Romney's father, George Romney, released 12 years of tax returns when he unsuccessfully sought the Republican nomination in 1968.

In excerpts of Biden's remarks released by the Obama campaign, Biden told the annual conference of the national Council of La Raza that Romney has released only one year of his tax returns, adding: "Making a lie of the old adage: Like father, like son."

The remarks underscored the Obama campaign's latest effort to portray Romney as secretive.

Biden also highlighted Romney's past hardline immigration stance. He said: "Mitt Romney wants you to show your papers, but he won't show us his."

Maria Castro, an 18-year-old recent high school graduate from Phoenix who was attending La Raza's conference, echoed Biden, saying of Romney: "I think it's hypocritical that he is holding the immigrant community accountable, but he won't be held accountable."

Biden also argued that Republican victories in November would result in policies that would suppress the right to vote.

"Imagine what the Supreme Court will look like after four years of Governor Romney," Biden said, according to the excerpts. "Imagine what it will act like. Imagine what it will mean for civil rights, voting rights, and so much we have fought so hard for."