I guess his speech writers are West Wing fans as well as Deval Patrick fans:

West Wing Season 2 Ep.2 (In the shadow of two Gunmen) 38 mins 50 sec

Bartlet: “what began on the commons in Concord, Massachusetts, as an alliance of farmers and workers, of cobbles man and tinsmiths, of statesmen and students,…”

Obama’s speech today (from Drudge)

Two hundred and twenty one years ago, in a hall that still stands across the street, a group of men gathered and, with these simple words, launched America’s improbable experiment in democracy. Farmers and scholars; statesmen and patriots who had traveled across an ocean to escape tyranny and persecution finally made real their declaration of independence at a Philadelphia convention that lasted through the spring of 1787.