Maybe you can’t, as the adage says, go home again.

A tipster tells us that Sen. Tom Udall had to show his Congressional ID to Capitol Police officers Wednesday morning in order to board a subway from the Rayburn House Office Building to the Capitol.

The New Mexico Democrat and former Congressman has only been out of the House for two years, but apparently that’s enough time to be forgotten.

“All that Senate wisdom has made him practically unrecognizable,” Udall spokeswoman Marissa Padilla quipped.

While some Members may have reacted by throwing a fit and yelling, “Do you know who I am?” (here’s looking at you, Louisiana Republican Sen. David Vitter), we hear Udall was polite and obliged the request.