Joe Biden and Barack Obama

It’s the commander-in-chief — leading a poolside invasion!

President Obama, armed with a Super Soaker, showed he’s the undisputed ruler of backyard fun, according to this photo posted by Joe Biden on the veep’s Twitter page.

Biden posted the pic this week under the heading: “Favorite Joe photos, volume 1.”

The photos were taken last weekend during a backyard “beach party” at the vice president’s residence.

The White House responded by putting up a picture showing Obama and the vice president high-fiving in a gym.