“If you can’t/don’t stand behind our troops, (feel free to) stand in front of them” is a patriotic saying that has been put on gift items such as bumper stickers and T-shirts. The saying has been cited in print since at least September 2006.
 
   
9 September 2006, Coshocton (OH) Tribune, Judi Conrad letter:
Proud to have a bumper sticker displayed on my daughter’s car that says, “If you can’t stand behind our troops, stand in front of them.”
     
Tangler.com Discussion Forum
Funny Bumper Stickers. 
Kevin 
03 Dec 07, 4:12 PM
IF YOU DON’T STAND BEHIND OUR TROOPS…
...FEEL FREE TO STAND IN FRONT OF THEM
www.supportsticker.ca
 
MacRumors Forums
Bumper stickers you’ve seen lately..  
juanster
May 20, 2007, 10:25 AM
Canadian army sticker:
“If you don’t stand behind our troops, feel free to stand in front of them.”
 
Google News Archive
26 November 2007, St. Petersburg (FL) Times, “Baseball, Wal-Mart and other matters of location” by Ernest Hooper, pg. 1B, col. 5:
Seen on a bumper sticker: If you can’t stand behind our troops, stand in front of them.
 
Google Books
The Slip Kids
And Levi Pender
By (?)
Iuniverse Inc
2011
Pg. 52:
Three, like the bumper sticker, IF YOU DON’T WANT TO STAND BEHIND OUR TROOPS FEEL FREE TO STAND IN FRONT OF THEM, he’s delusional and his own worst enemy.
 
Pittsburgh (PA) Post-Gazette
For our soldiers in Iraq, a little means a lot
2012-03-17 05:46:54
(...)
The T-shirts they’re sending say, “If you don’t stand behind our troops, feel free to stand in front of them.’’
 
LewRockwell.com Blog
Would They Shoot?
Posted by Laurence Vance on May 6, 2012 01:53 PM
I occasionally read about or receive pictures of signs that say: “If you don’t stand behind our troops, feel free to stand in front of them.” Here is an example:
(...)
It is always deceived warmongers who equate opposition to the Iraq and Afghan Wars with treason who hold up these signs. The question is, would U.S. troops shoot at Americans if they were in front of them? The police already do and get away with it (see Will Grigg).