Joking with the parents

Some background, I am American-Mexican (I know most of the United States says Mexican-American, just ask Cheech and Chong) but I am American first, of Mexican heritage.

Continuing, sometimes jokes go over my parent's head.  The only thing worse than telling a bad joke is having to explain why the bad joke is funny.

I told a joke that was (in my opinion) hilarious.  As much as I want to take credit for this joke it has to go to Gary Johnson.

Here goes (I'll use a pic):

My parents don't follow politics too closely but they are usually in tune to the major things (like Trump building a wall type stuff).  Unfortunately for me I had to explain this joke to my mom.  She starts laughing uncontrollably. She likes the joke so much (now that she understands) that she passes the phone to my dad and tells me to tell him.

I repeat the joke to my dad.  He also doesn't get it.  He is usually a little more up to speed with politics than my mom.  Unfortunately I had to explain the joke to him as well.  

 Instead of laughing at the joke he asked me "why would the Mexicans pole vault when they normally dig tunnels?"

I got to admit, this caught me off guard.  He has done this before, catching me off guard with his jokes/statements.  He once told me our family couldn't be called wetbacks because we crossed the Rio Grande when it was ankle deep (just to clarify, both me and my parents were born in the US, just a joke).