New little girl arrives at White House. Meet Sunny Obama.

If you want a friend in Washington, the saying goes, get a dog. And if you already have a dog? Get another one!

That’s the big news from the White House, where the Obamas have just welcomed the newest member of their family -- a little girl named Sunny, who is a Portuguese Water Dog like Bo. In fact, Sunny might be a friend mostly for five-year-old Bo, who wasn’t getting “enough dog interaction,” first lady Michelle Obama told reporters last fall.

Sunny was born in Michigan in June 2012, and arrived at the White House on Monday. Both Obama parents heralded her arrival on social media.

Mrs. Obama posted a picture of both dogs at 7:45 p.m. That's Sunny on the right, Bo on the left. 

“Sunny is the perfect little sister for Bo – full of energy and very affectionate – and the first family picked her name because it fit her cheerful personality,” a White House blog post said Monday night.

The Obamas also announced that they are are making a donation to the Washington Humane Society in honor of Sunny.

No word yet on the reaction to Sunny’s arrival from the Obama girls, Malia and Sasha, but we’ll assume they’re delighted.

Bo arrived soon after their dad’s first inauguration – a campaign promise kept, with an assist from the late Sen. Edward Kennedy (D) of Massachusetts, who sent the dog as a gift. Given the latest polls, Sunny’s arrival might look a bit like a diversionary tactic from all the bad news – the unrest in Egypt, the Edward Snowden saga, chronically high unemployment. Obama is in the midst of his annual August slump, with his Gallup daily tracking polls averaging below 46 percent.

But if a 2012 George Washington University study is to be believed, presidential pets aren’t that helpful during tough economic times. During times of war or scandal, yes, but not when the economy is struggling.

"We surmise that diversionary pets are a political liability when their frolicking on the White House lawn in hard times might cue the public that not everyone in the country is suffering equally and that being president is not a full-time job," the study concludes.

So perhaps Sunny’s main role will indeed be to help Bo run off some of his energy, with White House press releases of frolicking dogs kept to a minimum. Though we have to admit, the video footage of the two dogs embedded in the White House blog post Monday night is pretty cute. They’re easy to tell apart. Sunny looks to be all black, while Bo has distinctive white paws and chest.

But one thing is certain: There won’t be a litter of Portuguese Water Dogs at the White House anytime soon. Bo is neutered.