They are of different generations and from different Americas, their political lives separated by philosophy and circumstance, but on Monday at the White House, President Obama and former president George H.W. Bush and their families will unite under the banner of volunteerism.

At an afternoon ceremony in the East Room of the White House, Obama and Bush together will honor a retired couple from an Iowa farming town fittingly called Union, who have helped deliver free meals to hungry children around the world.