The U.S. presidential campaigns were trying to win older voters Friday, with a new video by President Obama's campaign arguing that Republican rival Mitt Romney derides seniors behind closed doors. 

The race for the November election remains tight, though Obama holds a slight lead in recent polls and has pulled ahead in cash on hand for the crucial final campaign push. 

Romney's running mate, Paul Ryan, brought along his 78-year-old mother for an appearance before the national convention of the AARP, a nonpartisan group that claims to have 37 million members age 50 and above. Ryan told attendees that he and Romney care about senior citizens. 

"Mitt Romney and I share your concerns," Ryan said in remarks provided by the campaign in advance. "And we respect you enough to level with you." 

Ryan argued that Obama's widespread health care overhaul has weakened Medicare, the popular federal entitlement program for seniors, and said Romney would give seniors more choice in their health care coverage if elected.