Voters were frustrated by a 2012 presidential race they called more negative than usual and more devoid of substantive discussion of issues, according to a survey released Thursday by the Pew Research Center. …

Two-thirds of registered voters surveyed after Election Day said they believe relations between Democrats and Republicans will stay the same or worsen over the coming year.

Optimism over President Obama’s chances for success stands at 56 percent, down from the 67 percent who envisioned success for the newly elected Democratic president four years ago.

An election marked by superPACs and negative ads left 68 percent of those surveyed saying there was more “negative campaigning and mudslinging” than normal, compared to 54 percent just four years ago. That neared the 72 percent who called the 2004 race between President George W. Bush and Sen. John Kerry as more negative than normal, and tied the 68 percent who viewed the 1992 contest between President George H.W. Bush, Democrat Bill Clinton and independent Ross Perot that way.