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Senator Chris Coons announced his support for the Iran nuclear deal on Tuesday when he spoke at the University of Delaware.Credit Kyle Grantham/The News Journal, via Associated Press

Good Wednesday morning. In their arguments against the Iran nuclear deal, some Republican candidates have mockedPresident Obama for calling climate change the most serious threat facing the nation. It is worth noting then that the deal’s success might be assured while Mr. Obama is in the Arctic, warning of the effects of climate change.

Mr. Obama may be in the wilds of Alaska, but he is on the verge of a major foreign policy victory back home: The Senate is a vote short of making it impossible for opponents to block the nuclear deal with Iran.

Senators Bob Casey of Pennsylvania and Chris Coons of Delaware, both Democrats, said on Tuesday that they would vote against a resolution putting Congress on record against the Iran deal, becoming the 32nd and 33rd Democrats to do so. Thirty-four votes are needed to sustain a presidential veto if the resolution of disapproval passes.

Now attention is turned to the 11 Democrats who have not officially disclosed their view, several of whom are widely expected to back the agreement.

Senator Benjamin L. Cardin of Maryland, the senior Democrat on the Foreign Relations Committee, has public appearances on Wednesday, but indications are that he will not announce his position on the Iran deal. Other Democratic senators being watched closely include Barbara A. Mikulski of Maryland; Joe Manchin III of West Virginia, who is believed to be leaning toward supporting the deal; Mark Warner of Virginia; Heidi Heitkamp of North Dakota, and Gary Peters of Michigan.

In the House, Democrats have maintained a steady parade in favor of the deal, and supporters of the president are optimistic they can keep Republicans from getting near the 290 votes required to override a presidential veto there. And if the House can sustain the veto, the Senate wouldn’t even have to vote a second time. With the votes to sustain a veto almost in hand, some Democrats are now pushing for the party to filibuster the deal on the Senate floor, avoiding a veto fight they say could weaken the president internationally even though the agreement would still go into force without majority congressional support.

— Carl Hulse

Stay tuned throughout the day: Follow us on Twitter @NYTpolitics and on Facebook for First Draft updates.What We’re Watching

For candidates, and potential candidates, the late-night talk shows seem to be an offshoot of the Sunday morning news shows, as Donald J.Trumpis expected to soon follow Gov. Chris Christie of New Jersey to “The Tonight Show With Jimmy Fallon,” while Senator Bernie Sanders of Vermont,Jeb BushandVice President Joseph R. Biden Jr. are all scheduled to appear on “The Late Show With Stephen Colbert” during his first several shows.

Mr. Biden will travel to Miami on Wednesday where he will speak at the Science Center at Miami Dade College, his office says, on the importance of “partnerships between community colleges and employers” in “helping Americans obtain the skills they need to succeed in the work force.”In the evening, he will speak at a Democratic Senatorial Campaign Committee event.

A Pro-Biden Group Plans for a Potential South Carolina Team

Mr. Biden may not have decided whether he will run for president, but his enthusiasts are not waiting to set up the makings of a South Carolina organization should he join the race.

The Draft Biden effort has settled on two well-known South Carolina Democrats to lead the initiative in the state, Inez Tenenbaum, a former state superintendent of education, and State Senator Gerald Malloy.

The staff of the South Carolina draft effort, which could ultimately become Mr. Biden’s “super PAC,” will be led by Isaiah Nelson, who last year ran the coordinated campaign for the South Carolina Democratic Party.

Mr. Nelson worked under Dick Harpootlian, an outspoken Biden supporter and the state Democratic Party chairman at the time, and the former executive director Amanda Loveday. Should Mr. Biden enter the race, Ms. Loveday is also expected to play a role for him in South Carolina.

— Jonathan Martin

Our Favorites From The Times

Like Mr. Trump, Ben Carson, a retired neurosurgeon, has never held elected office, but polls suggest that voters are responding to his low-key style.

CNN has changed its criteria to qualify for its debate in September, a move that effectively helps candidates who have moved up in the polls since the first debate — chiefly Carly Fiorina.

And Mr. Obamais in legacy-building mode in Alaska, where he has been talking about the rapidly unfolding effects of climate change and the urgent need to address it, and has been crossing some items off his bucket list.

Bulletins: New Trump, Brooklyn Bernie, and Old Trump

Mr. Trump, whose caustic statements on immigration have caused some controversy, took a step to try to smooth things over with Hispanics by invitingJavier Palomarez, president of the United States Hispanic Chamber of Commerce, to his Manhattan office.

While voters seem to be increasingly gravitating to Mr. Sanders‘s message, his candidacy raises another question: Is the nation finally ready to embrace a politician from Brooklyn?

And The Times’s About New York columnist Jim Dwyerwrites of an encounter with Mr. Trump nearly 18 years ago that suggests his demeanor as a presidential candidate is far from new.

What We’re Reading Elsewhere

The A.F.L.-C.I.O. has hinted it might delay its endorsement as a means in part to tilt the candidates toward more favorable positions, but Richard L. Trumka, the leader of the labor group who met privately with Mr. Biden last week, told reporters on Tuesday that he was open to an endorsement sometime before the first voting contests.

Yahoo Politics takes a look at Mr. Biden‘s potential 2016 run for president through the lens of his previous two, “in 1988 (when he pulled out of the race amid a plagiarism controversy before voting began) and 2008 (when he dropped out after coming in fifth in the Iowa caucuses).”

And New York magazine says that Mitt Romney is frustrated at Mr. Trump‘s success and how he is achieving it, which is “restarting ‘Mitt 2016’ talk.”

And WMUR in New Hampshire reports that Mr.Christie is releasing a new ad about the growing heroin epidemic in the state.

While many other aides to Hillary Rodham Clinton are deferential in their emails to her, one former aide, Cheryl Mills, her former chief of staff, is “the only person who says no to Hillary,” Politico reports. “She can be brusque, sometimes responding to Clinton’s questions with a simple ‘y’ as if she is too busy to finish typing the three-letter word.”