Who married who?

From:  "Cyndy:

What president's grandson married another president's daughter?

TB faithfully responded with this: 

David Eisenhower, grandson of Dwight D. Eisenhower, married Julie Nixon, President Nixon's daughter.

SaxonJF shared this knowledge: 

This is an easy one. Dwight David Eisenhower's grandson, David, married Julie Nixon, younger of two daughters of Richard Milhous Nixon, Eisenhower's VP, and later President.
There are pictures of David and Julie sitting next to each other as children, and the captions always announce, "they later married."
Thank goodness my bottomless well of Presidential trivia finally paid off.

Joe concluded with this: 

Nixon's daughter married Eisenhower's grandson.