You can always tell a Marine...

...but only former Marines can tell jokes about them.
Rico says his friend Tex, a former Marine, sends this:

A Marine squad was marching north of Fallujah when they came upon an Iraqi terrorist who was badly injured and unconscious. On the opposite side of the road was a Marine in a similar but less serious state. The Marine was conscious and alert and as first aid was given to both men, the squad leader asked the injured Marine what had happened.
The Marine said: 

I was heavily armed and moving north along the highway here, and coming south was a heavily armed insurgent. We saw each other and both took cover in the ditches along the road.
I yelled to him that Saddam Hussein was a miserable, lowlife scum bag who got what he deserved. and he yelled back that Barack Obama is a lying, good-for-nothing, left wing Commie who isn't even an American. So I said that Osama bin Laden dresses and acts like a frigid, mean-spirited lesbian! He retaliated by yelling: Oh yeah? Well, so does Nancy Pelosi!
There we were in the middle of the road, shaking hands, when a truck hit us.