From the NY Times:
Peter Koo, one of only five Republicans on the 51-member City Council, is set to announce early next week that he will switch parties to become a Democrat, according to people briefed on the decision.
Mr. Koo was elected in 2009 from the Queens district previously represented by John C. Liu, a Democrat who is now the New York City comptroller. His election came as a bit of a surprise — at least to people who live outside Flushing — because the district is strongly Democratic. But Mr. Koo, who spent more than $277,000 of his own money and received the endorsement of Mayor Michael R. Bloomberg, is a well-known community leader and has been called “mayor of Flushing” by some.
Mr. Koo has also been a strong supporter of Mr. Liu, who is considering a run for mayor, and was listed as a bundler of donations in Mr. Liu’s recent campaign finance filing — though for a relatively small amount: $7,200.
There were differing accounts, from people familiar with his decision, about his motivation. Some said that he did not feel appreciated by the Queens Republican party and that infighting in the county organization had made him increasingly uncomfortable. One person who had been briefed on his decision said Mr. Koo believed that as a Democrat, he could get more city money for his district, could increase his odds of becoming a Council committee chairman and could do more to support aspiring Asian-American politicians in the city.
No, it's because there's no competition if he runs as a Democrat. You need that spelled out for you?