The race for endorsements among Republican presidential candidates has been a slow one since we began keeping track of the endorsement primary earlier this year. Jeb Bush has sat atop our leaderboard, but many of his endorsements came before he officially announced his candidacy, and he’s received only three since Labor Day — all from House members.

But this week, Marco Rubio has shown signs of momentum, picking up endorsements from three fellow senators, including one today from Sen. James E. Risch of Idaho. In contrast to Bush’s 3 endorsement points since Labor Day, Rubio has received 22 — by far the most of any Republican candidate over that span.