When Hillary Clinton travels to Capitol Hill on Tuesday as part of her lawmaker charm offensive, she could be in for a slightly awkward encounter.

Bernie Sanders — the Independent who caucuses with Senate Democrats — will be sitting there at the weekly lunchtime meeting, as he always does, while the front-runner talks to her former colleagues.

It’s hardly unusual for rival presidential candidates to gather together on the Hill — four Republican senators are currently running against each other, and other candidates occasionally visit — but in Clinton and Sanders’ situation, the tension is a tad thicker.