How do we know that the heat is rising on Anthony Weiner?  The New York Times reports that Democrats are not going to take no for an answer to their demands for Weiner’s resignation.  Weiner’s hometown paper notes that the demands for an end to Weiner’s presence in Congress began yesterday with a key ally of Nancy Pelosi, Rep. Allyson Schwartz, and that sent a signal to the rank and file to follow suit:

The first — and most notable — call for Mr. Weiner’s resignation came on Wednesday afternoon from Representative Allyson Y. Schwartz, Democrat of Pennsylvania, a Pelosi ally who is overseeing the recruitment of the party’s candidates for the 2012 election cycle.

Pelosi called for an ethics investigation into Weiner’s activities within minutes of his confessional press conference.  That could have been seen as either a message to Weiner or as a way to clear the air and corroborate his position that he did not use government resources on his sexting spree.  Schwartz’ demand makes it clear that Pelosi intended the former rather than the latter, and her caucus quickly responded:

After Ms. Schwartz, a parade of rank-and-file Democrats across the country joined in, including Representative Mike Ross of Arkansas, Michael H. Michaud of Maine, Niki Tsongas of Massachusetts, Larry Kissell of North Carolina and Joe Donnelly of Indiana.

Mr. Ross, after a speech in his district, said, “I’m very disappointed in his actions.”

“I think he should resign immediately,” he added, “and I think all the appropriate authorities should investigate this matter.”

Hours earlier, Representative Steve Israel of New York, the chairman of the Democratic Congressional Campaign Committee, spoke to Mr. Weiner by phone, bluntly expressing frustration that Mr. Weiner’s political standing was deteriorating as new and more embarrassing details of his online relationships were emerging. On Wednesday morning, a photo surfaced on Twitter that was said to be an image of Mr. Weiner’s genitals that he had sent to a woman online.

The Times also reports that this is just the beginning.  If Weiner doesn’t agree to resign, they plan on bringing a parade of Democrats to Capitol Hill next week when Congress returns to demand Weiner step down.  Other Democrats not currently in office are filling the void in the meantime, including former Pennsylvania governor Ed Rendell, and his staff is looking for other jobs:

“I think this picture puts it over the limit, and I think he has no choice but to resign,” Rendell told Chris Matthews on “Hardball” Wednesday evening. “What I think Anthony Weiner should do is, he still has a lot to offer, he should resign, he should get treatment, and I mean real treament, maybe inpatient treatment, and if he can rehabiliate himself, can he someday down the road in New York run for office? Maybe, maybe. But he’s got to resign. He owes it to the party, he owes it to Congress, and he owes it to the issues he fought for.”

The dam is breaking on Weiner as he battles to save his career from a sex scandal made for the Internet age: In addition to the two former DNC chairmen, six House Democrats and two Democratic senators had called for his resignation by Wednesday evening. Democratic sources told POLITICO that members of Weiner’s staff were looking into new job opportunities. Some New York Democrats are starting to float the names of potential Weiner successors. Had the House been in session, the dam could have given way completely.

Two weeks ago, Weiner was a progressive crusader who had built a following through frequent television appearances and a special mastery of the social media tools Facebook and Twitter. As it turns out, his undoing was rooted in his facility with those Internet-age instruments. Now, colleagues said, he has embarrassed not only himself but his constituents and the institution of Congress. He has provided endless fodder to late-night comics while ruining a political future that seemed destined for the New York mayor’s office.

Yesterday, I told KOIN’s Nick Emmons (disclosure: Nick is my cousin) that Democrats won’t take too much damage from this scandal, mainly because the corruption in this case is entirely personal rather than political. Still, Weiner is an embarrassment, and they’re acutely unhappy with his continued presence as a distraction — and perhaps to protect themselves from being seen as tolerant of the creepy and predatory behavior Weiner demonstrated:

I’d guess that Weiner will probably cave by tomorrow afternoon and resign in the face of so much anger and rejection by his colleagues. If any further revelations surface, it might happen today. But if Weiner hasn’t resigned by the end of next week after the House comes back into session, don’t expect him to resign at all.

Update: According to CNN, Weiner hasn’t budged:

Despite mounting calls from even some fellow Democrats for him to resign, Rep. Anthony Weiner has told colleagues he has no plans to do so, a Democratic source told CNN Thursday.

Weiner told a House Democratic colleague from New York on Wednesday afternoon that he does intend to step down, the source familiar with the conversation said.

Weiner also said his wife, Huma Abedin, wants him to stay in Congress, and he cited polling data showing a majority of New York City voters want him to remain in office, the source said, describing Weiner as “dug in.”

That won’t come as good news to Senator Pat Leahy, who added his voice to the growing chorus of Democrats urging Weiner to step down:

Leahy “supports Minority Leader (Nancy) Pelosi’s request for a House investigation, and he believes that a decision by Congressman Weiner to voluntarily leave office would be in the best interests of his constituents and the House,” Leahy spokesman David Carle said.

How long can Weiner stay “dug in”?

Update II: CNN erroneously wrote the original report to say that “he does intend to step down,” which was the opposite of what they were reporting.  They have corrected the report now:

Rep. Anthony Weiner has said he has no plans to resign and that his wife wants him to stay in Congress, a Democratic source told CNN Thursday.

Weiner made the remarks to a House Democratic colleague from New York on Wednesday afternoon, rejecting growing calls from fellow lawmakers — including key Democrats — for him to step down, said the source, who was familiar with the conversation.

Weiner also cited polling data showing a majority of New York City voters want him to remain in office, the source said, describing Weiner as “dug in.”

I never noticed it when I first posted the story.  Thanks to Brian Faughnan for pointing it out.