The root of Progressivism in America was in the 1880s.
Woodrow Wilson states that the Founders’ conception of government and society is mechanistic and “Newtonian,” whereas the Progressive vision is evolutionary and Darwinian.
Progressivism is a movement intent on “progressing” or moving beyond the principles and practices of the American founding. Early progressives argued that rights do not come from nature and are thus not inalienable. Rights are therefore granted by government. In the late 19th century the progressives argued that industrialization. Immigration and economic advances were no longer operative or valid and they did not believe that the Constitution sufficiently accounted for changes in the American way of life that occurred in the late nineteenth century and did not mask their criticism of the Constitution and the Declaration of Independence. The Constitution’s internal arrangement of Federalism, separation of powers, checks and balances was particularly abhorrent to the Progressives, for it impedes the government’s ability to deal with policy needs as they arise. The core Progressive doctrine of historical contingency means there are no permanent or immutable principles. Rather, they are dependent upon the particular circumstances of history and the belief that human nature is changeable.
This is an alphabetical list of all members of the Congressional Progressive Caucus (CPC) as of April 2011:
Tammy Baldwin, Karen Bass, Xavier Becerra, Earl Blumenauer, Robert Brady, Corrine Brown, Michael Capuano, Andre Carson, Donna Christensen, Judy Chu, David Cicilline, Yvette Clarke, William "Lacy" Clay, Emanuel Cleaver, Steve Cohen, John Conyers, Elijah Cummings, Danny Davis, Peter DeFazio, Rosa DeLauro, Donna Edwards, Keith Ellison (co-chair), Sam Farr, Chaka Fattah, Bob Filner, Barney Frank, Marcia Fudge, Raúl Grijalva (co-chair), Luis Gutierrez, Maurice Hinchey, Mazie Hirono, Michael Honda, Jesse Jackson Jr., Sheila Jackson-Lee, Eddie Bernice Johnson, Hank Johnson (whip), Marcy Kaptur, Dennis Kucinich, Barbara Lee, John Lewis, David Loebsack, Ben Ray Lujan, Carolyn Maloney, Ed Markey, Jim McDermott, James McGovern, George Miller, Gwen Moore, Jim Moran, Jerrold Nadler, Eleanor Holmes Norton, John Olver, Frank Pallone, Ed Pastor, Donald Payne, Chellie Pingree, Jared Polis, Charles Rangel, Laura Richardson, Lucille Roybal-Allard, Bobby Rush, Linda Sanchez, Bernie Sanders (CPC's lone Senator), Jan Schakowsky, Jose Serrano, Louise Slaughter, Pete Stark, Bennie Thompson, John Tierney, Nydia Velazquez, Maxine Waters, Mel Watt, Henry Waxman, Peter Welch, Frederica Wilson, and Lynn Woolsey.
The following individuals were members of the Congressional Progressive Caucus at various times prior to April 2011:
Neil Abercrombie, David Bonior, Sherrod Brown, Roland Burris, Julia Carson, Diana DeGette, Lane Evans, Eni Faleomavaega, Earl Hilliard, Stephanie Tubbs Jones, Eric Massa, Cynthia McKinney, Carrie Meek, Major Owens, Nancy Pelosi, Lynn Rivers, Gus Savage, Robert Scott, Hilda Solis, Linda Stender, Tom Udall, Diane Watson, Paul Wellstone, and Robert Wexler.
No matter what name they hide behind, the progressives/liberals/socialists have been well-defined for quite some time -- here's a nice link to a translation of The Law, in which Bastiat seemed to nail it perfectly so long ago.
Thank you JW for the extensive info/links--appreciate the effort :)