The two ran into each other in the concourse of at the capitol, and parted ways in high spirits. I happened to be walking by at the same time and photographed the meeting. Afterward, Rivera asked me to the publish the photo. Then he turned around and starting filming other people walking by.

"With Fernando Cabrera, working class people in the 14th district will finally have representation in the City Council,” the hotel workers union president, Peter Ward, said in a public statement.

Cabrera also has the backing of the Bronx Democratic County establishment, whose leader ousted Baez ally Jose Rivera in a coup last year.

The two unions also endorsed Assemblyman Mark Weprin in his race for the City Council seat in Queens being vacated by his brother, David, who’s running for comptroller.

Eighteen members voted no. They were:

Alan Maisel, Hakeem Jeffries, William Colton, Jim Brennan, Peter Abbate, Nick Perry, Annette Robinson, all of Brooklyn; Jeff Aubry and Mark Weprin--who is running for City Council--both from Queens; Carl Heastie, Marcos Crespo, Vanessa Gibson, Nelson Castro, Jose Rivera, and his daughter Naomi Rivera of the Bronx, and Danny O’Donnell and Deborah Glick of Manhattan.

The senators, who cost the Democrats support of the State Senate by crossing the aisle to provide the 31st and 32nd votes to Republican leader Dean Skelos, come from overwhelmingly Democratic districts and will both, in theory, be highly vulnerable to party-backed primary challenges.

But, assuming Espada and Monserrate are still around next year--and that they haven't cut some sort of deal with the party by then to flip back--who will do the challenging?

Here, with the help of some smart readers, are a few speculative candidates.

Espada has a number of political committees, but none show how much campaign money he has on-hand for re-election.

Potential challengers to him are:

Hector Ramirez: He’s a county district leader who is Dominican, and an officer of the Bronx Democratic County Organization. When reached on his cell phone this morning, he said he wanted to take a wait-and-see approach, saying things could change a lot before next year's race.

Nelson Castro: He’s an assemblyman of Dominican descent and once worked as chief of staff to Assemblyman Adriano Espaillat of Manhattan. He would need a major influx of campaign cash. Currently, he’s $1,953.12 in debt. A message left at his Assembly office was not immediately returned.

Ramdes Perez: Puerto Rican businessman who has money already, but would have to move into the district by Election Day. Where he’s been running and doing a lot of work in the district already as part of the City Council race he ultimately withdrew from. A message left on his cell phone was not immediately returned. He's raised $156,945 for his Council race.

Yesina Polanco: She was the chief of staff to City Councilwoman Annabel Palma, and is running against City Councilwoman Maria Baez right now. She also worked as the chief of staff to Assemblyman Luis Diaz. She’s Puerto Rican, as is a majority of voters in that part of the Bronx. In a brief conversation this morning, Polanco said no matter the outcome of her election this year, she would not run. Still, her name is out there.

Jose Rivera: He’s an assemblyman and former Democratic county leader of the borough who was deposed in a coup last year. He’s well known in the community and in political circles, but may not have the political support (yet) to be the candidate. A spokesman for Rivera, Michael Nieves, said Rivera and Espada are "on the same side" and discounted the notion that siding with the Republicans in this leadership fight would warrant any kind of primary challenge.

The district:

Espada's district includes neighborhoods represnted by Assembly members Jose Rivera, and Nelson Castro, and council members Joel Rivera and Maria Baez. Politically, it’s also considered the front line in the civil war in the Bronx Democratic County Organization, between the new leader, Carl Heastie, and allies of the leader he overthrew, Jose Rivera. In this uncontrolled territory, Espada unseated a deeply troubled incumbent whose legal woes were, somehow, worse than Espada’s.

There’s 114,537 Democratic voters in the district, only 9,139 Republicans, and 22,0071 voters not registered in any party.

Monserrate has $137,790.27 on hand right now for reelection next year. Right now, there is still an effort by Democrats to woo Monserrate back. If that fails, a primary challenge could be expected. Mentioned as potential challengers are:

Jose Peralta: He’s an assemblyman with strong ties to labor. He’s had an on-again, off-again relationship with Monserrate that was, before the coup, in good standing. He’s been elected to district that largely overlaps with Monserrate's, and is one of the first people critics of Monserrate would turn to. Peralta also is well liked by the Queens Democratic County Organization. It’s unclear though if Peralta would take on the challenge. He does have $18,059.15 on hand already. A message left on his cell phone was not immediately returned.

Alfonso Quiroz: He’s an openly gay Latino who once worked for Mark Green’s mayoral campaign and for City Councilwoman Helen Sears. Most recently, he withdrew from the Council race in that area and is now backing Sears for reelection. He’s untested as a candidate, but generally has an unblemished record with the progressive community and labor unions. He didn't return an email request for comment.

John Sabini: He’s a former city councilman who is the last person to actually defeat Monserrate in an election. That was before Sabini was arrested for a DWI in Albany and lost the backing of the Queens County Democratic Organization to Monserrate in a rematch last year. Sabini took a job with the state instead of running. That DWI may pale in comparison to what Monserrate is accused of. But the district is changing demographically, and institutional types had gone on record last year saying that was one of the reasons they backed Monserrate over him. (He had an unusual counterargument). But still, Sabini is a known quantity in the area. A message left on his cell phone wasn’t immediately returned.

The district:

It’s sort of a no-man’s land, with ethnic rivalries and no strong, central power base. In that vacuum, Monserrate has built a formidable, self-sustaining political operation that propelled him to office, and his former chief of staff, Julissa Ferreras, to his Council seat (with some union help). While it’s also home base to the Queens County Democratic leader, Representative Joe Crowley, the county organization hasn’t been able to demonstrate any notable sway in the area.

There are 79,009 registered Democrats in the district, 12,227 registered Republicans, and 22,269 voters not registered with a political party.

UPDATE: In a brief interview, Sabini said, “I’m open to talking to people, but it’s not in my immediate plans.”

Quiroz emailed to say, "Currently I am focused on helping Council Member Helen Sears get re-elected."

Also, there’s Francisco Moya. He’s a district leader who once worked as an aide to David Paterson when he was still in the State Senate. Moya said he’s “definitely” interested in looking at a possible race against Monserrate next year. He currently works for Cablevision, and lost a race for the City Council in that area to Julissa Ferraras, who worked for Monserrate. Moya’s showing wasn’t entirely impressive in that outing, but in a potential primary, he could get more institutional support from unions and the Democratic establishment.

Bronx Democratic County Leader Carl Heastie said in a brief telephone interview that even though “there was always an assumption” he himself would try ousting Rivera, he isn't going to.

The assumption was out there, in part, because Joel is the son of Assemblyman Jose Rivera, the former Bronx Democratic leader that Heastie ousted in a dramatic coup last year.

“We’re not looking for a challenger against Joel,” Heastie said.

He’s looking to build lasting relationships with people who want to unite with his new entourage, Heastie said, not to make quick alliances to exact revenge.

“I don’t believe in political one-night stands,” Heastie said.

Speaking at a dinner in Riverdale last night, Dinowitz said electing Carl Heastie as the new Bronx Democratic leader was just the beginning of changes to come.

“With his leadership, I know there are going to be many more wonderful things happening in the Bronx. We got elections taking place this year. I won’t get into specifics , but, um, maybe there’ll be some changes in other district or districts for Council, for example,” Dinowitz said. “Not to name names.”

That got some oohs and aaahs from the crowd.

Later, Heastie assured City Councilman Oliver Koppell, “Oliver, I think Jeff was not talking about you.”

Dinowitz later told me he was indeed referring to Baez, who backed the former county leader, Jose Rivera, during the coup. Baez, at the time, also accused Dinowitz of “fighting, actually physically fighting with our delegates” during the county leader vote.

The endorsement caught my eye since the competitive race still includes at least one other established Democratic candidate, City Councilman Joel Rivera. According to reporter John DeSio—who launched a blog to cover this race—former state senator Israel Ruiz is considering running too.

(Since this is a special election, there won't be a primary, and candidates will run on their own lines.)

I emailed a spokesman for Bronx County Chair Carl Heastie to ask if the endorsement of Diaz marked a new policy of endorsing candidates running against other Democrats.

No, he responded, “this is not a primary. It is a nonpartisan special election.”

A bit of relevant local history: Diaz supported the coup that brought Heastie to power. Rivera is the son of the leader Heastie deposed, Jose Rivera.

So who will it be?

Since Carrion was going to run for comptroller, there are already a number of candidates organizing a campaign.

Leading the pack is Assemblyman Ruben Diaz Jr., who has raised $141,156 according to his January campaign filing.

There’s also City Councilman Joel Rivera, who has an even larger war chest, with  $207,451. But Rivera’s candidacy may suffer from the recent coup against his father, former Bronx Democratic County Jose Rivera, who was ousted by a faction led by Diaz.

In a brief telephone chat just now, Diaz said, “I’m concentrating on making sure I get my message out to Bronxites.”  He declined to comment on the impact an abbreviated campaign season may have on the race.

“I’m concerned about what it is I need to do to be the next borough president,” he said. He said he is still interviewing prospective staff, and aside from a treasurer, he has no campaign employees.

Also worth keeping in mind: if Carrion is confirmed, what happens to the $2 million he raised for his city comptroller race?

A spokeswoman did not immediately return a message seeking comment.

UPDATE: A reader who questioned the process for filling a borough-president vacancy noted that when Bronx Borough President Stanley Simon left his seat early before a corruption scandal in 1987, his replacement, Fernando Ferrer, was installed by the City Council.

But since that time, the law has been changed and the position is now supposed to be filled by a special election. Whenever the seat is vacated, a special election has to be held about 45 days later, according to attorney Jerry Goldfeder, who literally wrote the book on this stuff.

Here’s an invitation to an event for recently ousted Bronx Democratic leader Jose Rivera, who, it seems, wants to seek re-election to his Assembly seat. Rivera had come under criticism for using this year's county fund-raiser as a way to generate money for his own political efforts.

Rivera's replacement, Assemblyman Carl Heastie, said he hadn't known about the event before I contacted him. He didn't say whether he was going to attend, but did say, "I wish him well. He is still a member of the Assembly and since he told me is staying in the Assembly, he is doing what he has to do."

Heastie confirmed his victory with a quick text message to me, "thank u."