As has been said, there looks like plenty of contact area but it looks really short-grained. My choice of adhesive would be titebond.
In order to minimise slip I would dry fit the joint and drill two 2mm holes in areas where there is plenty of beef on both parts. In the UK our cocktail sticks ( I believe you call them toothpicks happen to be exactly 2mm in diameter.
Spread enough glue onto each part and fit together, placing the cocktail sticks into the holes at the same time, and clamp the joint as tightly as possible. The cocktail sticks prevent the joint from slipping, and fill the holes simultaneously. Clean up the excess glue while wet, and after the joint has cured, use wet n dry paper to flat the area in prep for refinishing (you wont get away with not refinishing unless you're not too fussy about detail).
Fortunately, from the looks of the pic, the colour is black so it should only need a very wuick blow in with a colour gun or airbrush before final coats of lacquer.