Half a dozen House Democrats attended the White House Congressional Ball last night while their colleagues on the Judiciary Committee worked late into the night on articles of impeachment, according to two sources familiar with the event.

Why it matters: If you're looking for clues about which House Democrats might vote against impeaching President Trump next week, one tempting place to start is with those who chose to be Trump's guests at the annual ball — but that doesn't mean the two lists will totally overlap.

Democrats attending the party included:

Antonio Delgado (NY-19): Trump won the district in 2016. Delgado is a first-term congressman and defeated a Republican incumbent in a close contest. Delgado is also the first African-American or Hispanic representative from upstate New York. His staff did not respond to requests for comment. Susie Lee (NV-3): Trump won the district in 2016. Lee is a first-term congresswoman who managed to keep the seat in Democrats' hands in a close general election race. Lee's staff previously said she's undecided on impeachment. A spokesperson confirmed that Lee attended the ball, saying it was a way to demonstrate that "she's committed to being a bipartisan problem solver through and through." Elaine Luria (VA-2): Trump won the district in 2016. Luria is Navy veteran and a first-term congresswoman who unseated a Republican incumbent in a tight race. Her staff did not respond to requests for comment. Jim Costa (CA-16): Trump lost the district in 2016. Costa has served in Congress since 2005, in the 20th and now the 16th districts. He represents an agricultural area. Costa could not be reached for comment. Josh Harder (CA-10) Trump lost the district in 2016. Harder is a first-term congressman who unseated a Republican incumbent in a close race. His staff did not respond to requests for comment. Gil Cisneros (CA-39): Trump lost the district in 2016. Cisneros is first-term congressman. He is also a Navy veteran, former Republican and a lottery winner. Cisneros' chief of staff Nic Jordan did not deny his boss attended the White House party, but shared tweets, including this one by CNN's Manu Raju, emphasizing that Cisneros will vote for impeachment, even though he may get "some blowback," because "this is about national security."

Independent Justin Amash (MI-3) also attended. Amash left the Republican Party earlier this year after he backed formal impeachment proceedings.

Amash's chief of staff Poppy Nelson said: "Rep. Amash has celebrated Christmas at the White House with his colleagues every year he has served in Congress."

Senator Tammy Baldwin (D-Wisc.) was also present, but her spokesman John Kraus said there is no link between her attendance at Trump's party and her thoughts about impeachment.

The two Democrats who voted against launching the impeachment inquiry — Jeff Van Drew (NJ-2) and Collin Peterson (MN-7) — were not spotted at the ball by our sources. Peterson's staff confirmed that he did not attend, and Van Drew's spokesperson did not respond to requests for comment

A senior White House official said of Trump's critics: "It's kind of odd to be voting to say the guy is a clear and present danger to the globe but I'm going to come and hang out at the White House for a black tie affair."

Earlier this year, the White House's acting chief of staff Mick Mulvaney and Legislative Affairs director Eric Ueland debated with Trump whether to invite just a certain group of congressional Democrats or all of them. POTUS ultimately told them to "invite them all," per two sources familiar with their conversation.

Editor's note: This story has been updated to reflect that Sen. Tammy Baldwin also attended the holiday party.