The vice president is expected to hammer Romney for not being forthcoming with his income tax records, contrasting the Republican with his father, former Michigan Gov. George Romney.

“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 is expected to say. “His son has released one year of his tax returns.”

“Making a lie of the old adage: Like father, like son,” Biden added. “Mitt Romney wants you to show your papers, but he won’t show us his.”