Both Senator Charles Schumer and Senator Kirsten Gillibrand will formally endorse City Comptroller William Thompson for mayor today in Union Square. However, City Room wonders, "But will Chuck or Kirsten actually say anything bad about Mike?"

That's because Schumer has previously praised Mayor Bloomberg, who also had Schumer's wife as DOT Commissioner for a while. Also, City Room notes, "Mr. Bloomberg also employs a number of former Schumer aides on his campaign, or in City Hall, including Bradley Tusk, his campaign manager; Howard Wolfson, a campaign spokesman; Josh Isay, a political consultant; and Stu Loeser, his chief spokesman in the mayor’s office." So the guess is that Schumer (and Gilly) will praise Thompson while not really blasting Bloomberg.

Bloomberg is currently an Independent, after switching from the Democratic Party to the Republican Party in 2001 (to win the election) and then dropping his GOP stripes in 2007, when he was considering a third party run for president. PolitickerNY points out, "Since unenrolling from the Republican Party in 2007 in a public gesture toward an independent presidential run, Bloomberg has sought to highlight his support from Democrats. This weekend, he announced he was endorsed by 'two prominent, longtime Democrats,' Peter Vallone Sr., the former Speaker of the City Council, and his son, Peter Vallone Jr., a Councilman in Astoria." And it's been rumored that President Obama is trying to stay out of the mayoral race because of his relationship with Bloomberg.

Thompson received the endorsements of City Council members Bill de Blasio and John Liu yesterday—all three are also Working Families Party candidates.