President Obama refused to reveal who received his vote when he went to the polls in Chicago, a reticence that tracks with Senate candidates who have refused to own up to their support for him.

“I can’t say that,” Obama replied when asked who he voted for, per the pool report. ”This is the most important office of democracy, the office of citizenry.”

That explanation is likely an attempt to provide political cover for Senate candidates such as Alison Lundergan Grimes. Grimes, the Democrat challenging Senate Minority Leader Mitch McConnell (R., Ky.), refused to say who she voted for in 2012, claiming that to do so would undermine the right to a secret ballot in Kentucky.

Obama’s spokesman was less helpful to Grimes when he laughed with the White House press corps about her silence.

“I’ll tell you that I voted for the president,” White House press secretary Josh Earnest said, smiling.