WASHINGTON -- Israeli Prime Minister Benjamin Netanyahu's speech to a joint session of Congress on Tuesday has further strained an already tense relationship with President Barack Obama. And a number of top Democrats --- including Vice President Joe Biden, whose job description includes the title President of the Senate --- won't be attending. Virginia Senator Tim Kaine is among the Democrats who will be absent from Netanyahu's speech. In a January letter to House Speaker John Boehner, Senator Kaine explained his absence:

As a long-time supporter of the U.S-Israel relationship, I believe the timing of Prime Minister Netanyahu's address to Congress – just days before Israeli elections – is highly inappropriate. On January 30, I delivered a letter to Speaker Boehner asking that the speech to Congress be postponed so that there was no appearance of U.S. favoritism in a foreign election. There is no reason to schedule this speech before Israeli voters go to the polls on March 17 and choose their own leadership. I am disappointed that, as of now, the speech has not been postponed. For this reason, I will not attend the speech.

Netanyahu is expected to use Tuesday's speech to sharply criticize the White House's efforts to negotiate a deal on Iran's nuclear program and to urge Congress to pass new sanctions on the nation, a position that puts him sharply at odds with the president. On Tuesday, National Security Adviser Susan Rice said Netanyahu's decision to speak was "destructive to the fabric of the relationship" between Israel and the U.S.

The expected substance of the speech, coupled with the fact that the White House was not alerted to the invite ahead of time, has Democrats crying foul.

At least 45 Democratic House members and eight Democratic senators have said in recent weeks they're not going to the speech, many in protest to a move that they say is an affront to the president. Many more have said they're undecided on whether to attend, and more defections could emerge in the coming days. A full list of the Democrats who have confirmed they're missing the speech follows:

SENATE - 8 members

Sen. Al Franken (Minn.), Sen. Martin Heinrich (N.M.), Sen. Tim Kaine (Va.), Sen. Patrick Leahy (Vt.), Sen. Bernie Sanders (I-Vt.), Sen. Brian Schatz (Hawaii), Sen. Elizabeth Warren (Mass.) and Sen. Sheldon Whitehouse (R.I.)

HOUSE - 45 members

Rep. Earl Blumenauer (Ore.), Rep. Corrine Brown (Fla.), Rep. G.K. Butterfield (N.C.), Rep. Andre Carson (Ind.), Rep. Joaquin Castro (Texas), Rep. Katherine Clark (Mass.), Rep. William Lacy Clay (Mo.), Rep. James Clyburn (S.C.), Rep. Steve Cohen (Tenn.), Rep. John Conyers (Mich.), Rep. Danny Davis (Ill.), Rep. Peter DeFazio (Ore.), Rep. Diana DeGette (Colo.), Rep. Lloyd Doggett (Texas), Rep. Donna Edwards (Md.), Rep. Keith Ellison (Minn.), Rep. Marcia Fudge (Ohio), Rep. Raúl Grijalva (Ariz.), Rep. Luis Gutiérrez (Ill.), Del. Eleanor Holmes Norton (D.C.), Rep. Eddie Bernice Johnson (Texas), Rep. Marcy Kaptur (Ohio), Rep. Barbara Lee (Calif.), Rep. John Lewis (Ga.), Rep. Dave Loebsack (Iowa), Rep. Zoe Lofgren (Calif.), Rep. Betty McCollum (Minn.), Rep. Jim McDermott (Wash.), Rep. Jim McGovern (Mass.), Rep. Jerry McNerney (Calif.) Rep. Gregory Meeks (N.Y.), Rep. Glen Moore (Wis.), Rep. Beto O'Rourke (Texas), Rep. Donald Payne (N.J.), Rep. Chellie Pingree (Maine), Rep. David Price (N.C.), Rep. Charles Rangel (N.Y.), Rep. Cedric Richmond (La.), Rep. Jan Schakowsky (Ill.), Rep. Adam Smith (Wash.), Rep. Bennie Thompson (Miss.), Rep. Mike Thompson (Calif.), Rep. John Yarmuth (Ky.), Rep. Karen Bass (Calif.) and Rep. Chaka Fattah (Pa.).

The CNN Wire contributed to this report.