[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2009/images/12/03/art.rogers1203.gi.jpg caption="Citing 'separation of powers,' the White House said Obama social secretary Desiree Rogers would not be testifying at Thursday's congressional hearing."]
Washington (CNN) - The White House is being accused stonewalling as Congress investigates the party-crasher security breach at President Obama's first state dinner last week.
At issue: Whether the White House is protecting Social Secretary Desiree Rogers from testifying about how Tareq and Michaele Salahi were able to crash the first White House state dinner. The couple did not have an invite but were allowed in.
Rogers' office planned the dinner.
Members of Congress put pressure on Secret Service Director Mark Sullivan Friday for the grate crashing fiasco. Sullivan said his agency will take the heat for the incident.
"This is our fault and our fault alone," he said. "There's no other people to blame here. ... Look at me and blame me," he told the House Homeland Security Committee.
Lawmakers praised his candor, but bluntly declared that Rogers should be facing tough questions too.