[tweed-l-duhm uh
n tweed-l-dee] 
| two persons or things nominally different but practically the same; a nearly identical pair. |
| twee·dle·dum and twee·dle·dee (twēd'l-dŭm' ən twēd'l-dē') n. Two people or two groups resembling each other so closely that they are practically indistinguishable. [After Tweedledum and Tweedledee, names of two proverbial rival fiddlers, of imitative origin.] |
tweedledum and tweedledee
Two matters, persons, or groups that are very much alike, as in Bob says he's not voting in this election because the candidates are tweedledum and tweedledee. This term was invented by John Byrom, who in 1725 made fun of two quarreling composers, Handel and Bononcini, and said there was little difference between their music, since one went "tweedledum" and the other "tweedledee." The term gained further currency when Lewis Carroll used it for two fat little men in Through the Looking-Glass (1872). For a synonym, see six of one, half dozen of the other.