Elizabeth Warren says she will not support Weiss’ nomination. (flickr/Senate Democrats)

President Obama is once again facing pushback on an executive branch nomination, but this time it’s coming from his own party.

Obama’s nomination of Lazard‘s Antonio Weiss to become the next under secretary for domestic finance at Treasury has raised the ire of the likes of Sen. Elizabeth Warren (D-Mass.). Weiss is currently the head of investment banking at Lazard.

The lines of demarcation in this internal proxy war among Democrats become clear with a look at Weiss’ political donation history.

Weiss was a bundler for Obama during the 2012 election, accounting for at least $200,000 in contributions to Obama’s re-election effort. He supported both of the president’s White House campaigns with gifts from his own pocket. Since the 2008 cycle, Weiss has contributed more than $140,000 to campaign efforts — all to Democratic candidates and committees.

The candidates Weiss gave to represent those at the opposite end of the party from Warren — at least when it comes to the financial sector. They include Sens. Charles Schumer (D-N.Y.), Mark Warner (D-Va.), Kirsten Gillibrand (D-N.Y.) and Cory Booker (D-N.J.). Geography aside, these four largely represent the pro-Wall Street wing of the party, and are among the top beneficiaries of financial sector donations.

Weiss and Lazard have stuck by Obama and the Democrats at a time when many on Wall Street are shifting their allegiance to the right in search of looser regulations. Lazard employees favored Democratic candidates with two-thirds of their donations during the 2014 cycle. Despite Wall Street’s shift to support Mitt Romney in 2012, Lazard gave more than 60 percent to Democrats.

Despite his party loyalty, Weiss’ nomination was condemned by Warren in a Huffington Post article published last month, in which she said that “It’s time for the Obama administration to loosen the hold that Wall Street banks have over economic policy making.” Rare would be the Wall Street nominee that Warren would support, it seems — Democratic donor or not.