It has been a mixed week for Barack Obama, the presumptive Democratic presidential candidate. On the one hand, a Reuters/Zogby poll announced that the junior senator’s 7-point lead over John McCain, the presumptive Republican presidential candidate, has dissolved into a 5-point deficit.

Senator McCain now leads him 46% to 41%. On the other hand, the press has discovered Senator Obama’s long-lost half brother, George Hussein Onyango (also spelled Owango) living quietly in Kenya. Among the rustics who compose the Democratic base, this discovery can only help Senator Obama.

According to the Reuters/Zogby poll, the Democratic frontrunner has slipped with almost every category of Democratic voters: Catholics, Evangelicals, vegetarians, nudists, flagpole sitters — you name it. Yet the slippage has been greatest among the senator’s core supporters, the liberals.

Among them he has dropped 12%. Part of the reason for this drop, Zogby speculates, is owing to the candidate’s efforts to sidle toward the political mainstream. Zogby mentions Mr. Obama’s switch from opposing all offshore oil drilling to accepting limited drilling.

Brother George will assuage the concerns of many of these liberals. According to the Italian edition of Vanity Fair, George lives in a hut in bucolic Hurma, Kenya, a few miles outside Nairobi. His residence is the epitome of “green,” using no electricity, cooled solely by gentle breezes, and with no plumbing to pollute nearby waters, if there are nearby waters.

George leaves almost no carbon footprint. He does not drive an automobile. In fact, he lives a very spartan existence, spending only “a dollar a month,” as he apprised VF in an exclusive interview; though other sources report an expenditure of a dollar a day. At any rate, his consumption of the world’s resources is minimal.

But, it is not completely accurate to say the brother George is Mr. Obama’s “long-lost” sibling, for he met his brother when George was 5-years-old, two decades ago. In “Dreams From My Father,” Mr. Obama’s autobiography, he recalls George as a “beautiful boy with a rounded head.”

George tells VF that the two met again in 2006 when Mr. Obama was touring East Africa and visiting Nairobi. Apparently the meeting did not go well. As George recalls it, “We spoke for just a few minutes. It was like meeting a complete stranger.” George is only 26, which could help his brother shore up the youth vote back in America, a vote that is often unreliable.

Frankly, I find it curious that Mr. Obama has not brought George onto the campaign trail with him. Perhaps he has been saving George for the Democratic National Convention. The convention will abound with so many of the enthusiasts who in the recent primary season plucked Illinois’s junior senator from relative obscurity and elevated him above the likes of Senators Clinton and Edwards in the presidential sweepstakes. I have in mind the environmentalists, the enemies of the giant corporations, the Angry Left, the Even Angrier Left — most of whom have never dirtied their hands in politics or, for that matter, any civic involvement whatsoever.

In his VF interview, it is apparent that George is well spoken and has experienced the ups and downs of life that are so enrapturing to Democratic convention goers — particularly the downs. Moreover, it would be prudent to get George out of Kenya, where his presence could be a Secret Service nightmare. For that matter, Mr. Obama has seven other half brothers living in far-flung habitats. The Secret Service will have its hands full keeping an eye on them.

If brother George does make an appearance at the Democratic National Convention he will surely outshine Mrs. Clinton’s brothers, who were so deeply implicated in the brokering of President Clinton’s last-minute pardons and in other questionable financial deals in the 1990s.

Mr. Obama’s boast of being aloof from the “same old Washington politics” can only be reinforced by his brother’s presence at the convention. George is the farthest thing from being one of those “Washington insiders” his brother inveighs against.

Finally, given our country’s low estate within the world community, who would make a more agreeable United States Ambassador to the United Nations than this exemplary Citizen of the World, George H. O. Obama?

Mr. Obama’s decline in the polls may be over.

Mr. Tyrrell is the founder and editor in chief of the American Spectator, a contributing editor of The New York Sun, and an adjunct scholar at the Hudson Institute.