BRANCHING OUT
Credit: LA Times Crossword  (#1-6)
Sylvia Bursztyn and Barry Tunick

The answers to the clues below will have something in common.

1. Rear-end rectangular message
2. Fuddy-duddy
3. Pertinacity
4. Potential bone-breakers
5. Armed robbery
6. What a shoplifter has
7. Child's drawing, often
8. City-street baseball
9. Issue which can't be resolve
10. Rural areas
11. Dismay at the price of a new car
12. Manual transmission
13. Stay close
14. Support and defend
15. British awkward situation

Answers:

1. Bumper sticker
2. Stick-in-the-mud
3. Sticking power
4. Sticks and stones
5. Stick-up
6. Sticky fingers
7. Stick figure
8. Stickball
9. Sticking point
10. The sticks
11. Sticker shock
12. Stick shift
13. Stick tight 
14. Stick up for (or by) 
15. Sticky wicket