An appeal to Latino voters? A dig at Mitt Romney for declining to release more of his tax returns?

How about both?

On Tuesday afternoon, Vice President Joe Biden made an address to the National Council of La Raza conference in which he trotted out a new double-barreled attack on the presumptive GOP nominee.

“Mitt Romney wants you to show your papers, but he won’t show us his,” Biden told the Las Vegas conference, according to his prepared remarks.

The provocative line’s debut comes as both campaigns are working to woo Latino voters.Last month Obama and Romney delivered back-to-back addresses at the NALEO conference of Latino officials, an event that came on the heels of Obama’s announcement that his administration will halt the deportations of some immigrants who were brought to the United States illegally as children.

Hector Barreto, former head of the Small Business Administration and co-chairman of Romney’s Latino outreach effort, responded by pointing out that Biden’s address “comes on the heels of yet another disappointing jobs report which showed that the second quarter of this year was the worst quarter of job creation in two years.”

Read the full story at the Washington Post