If you want a friend in Washington, Harry Truman once said, get a dog.

That's exactly what dozens of members of Congress have done. On any given day, it's not unusual to see the pups of politicos walking the halls of Congressional office buildings or frolicking on the grounds outside the U.S. Capitol. 

If you drop by the office of Congressman Ken Calvert, it’s likely you’ll first be greeted by a happy little golden dachshund. The Riverside Republican calls Cali "the smartest dog in the world." And then he goes nose-to-nose with the pooch in his lap to confirm it: "Isn’t that right, Cali?"

Calvert was originally a cat person. A stray adopted him back in the Inland Empire. But he decided he wanted a dog in D.C.

Like most everything on Capitol Hill, the selection of Cali was the product of intense negotiations. Staffer Rebecca Keightley offered to share custody of a dog with Calvert on one condition: "If I can bring her to work everyday."

Calvert lobbied for a dachshund, a breed he calls smart, sweet and stubborn — originally bred to flush out badgers from hollow logs.  Six-year-old Cali prefers more leisurely exercise: swimming every summer in the fountain outside the Rayburn House Office Building. Two years ago, the Humane Society of the United States named Cali “Barker of the House.” 

Calvert says Cali makes the office atmosphere "a little more friendly. Dogs are happy everyday generally."

There was one unhappy incident: former California Congressman Jerry Lewis brought his dog Bruin for a visit one day. The bichon poodle marked his territory…on Cali. 

There's also a pooch on the couch in the office of Democrat Linda Sanchez.

The Congresswoman from Lakewood says everybody vies for your time all day long on Capitol Hill. "People want to meet with you, they want to speak to you, constituents call." But going home to an empty studio apartment at night, she says, is "awfully lonely." 

Sanchez has a family back in California. Here in Washington, she has Chavo, a 13-year-old rescue beagle. "He’s got these soulful brown eyes and these long velvety ears. We call him our zen dog because he doesn’t bark and he doesn’t hurry." 

That was a problem the day there was a fire drill on Capitol Hill. Chavo refused to leave the office and had to be carried downstairs, "which was hysterical," Sanchez says, "because at that time Chavo more closely resembled a watermelon with feet." He’s since lost a few pounds – not by working out in the House gym, but by play dates with other Congressional canines who’ve turned a grassy area atop a parking garage into a bi-partisan dog park.

Like Calvert, Sanchez shares custody. Chavo spends weekends with a family whose 10-year-old was begging for a dog. Sanchez says that’s where the usually silent Chavo discovered his “inner hound,” howling at a deer in the woods behind his weekend home.

Dogs have a long history on Capitol Hill. 

Virginia Congressman John Randolph would bring an entire pack of hunting dogs with him on the floor of the House of Representatives in the early 19th century. Randolph was a big dog himself in Congress. As chair of the powerful Ways and Means Committee, he was the defacto floor leader for Thomas Jefferson's administration. Randolph's colleagues were not impressed. They wanted to get rid of the hounds. House Historian Matt Wasniewski says when one member complained, Randolph hit him in the head with a riding crop.

The Congressional dog policy changed in 1811, when Kentucky Congressman Henry Clay became Speaker. Wasniewski says one of Clay's first actions was to turn to the doorkeeper, ordering him, "Remove the beasts from the floor!" 

Randolph was furious. The dispute had political fallout: Clay and Randolph clashed over the War of 1812, the Missouri compromise, and finally, in 1826, fought a duel. Neither man was shot.

And while dogs have the run of most of Capitol Hill, to this day they are still not welcome on the floor of the House of Representatives.