House Democrats have clamped down on internal divisions ahead of an expected vote to constrain President Trump's ability to wage war with Iran, Axios has learned from lawmakers familiar with the matter.Why it matters: That apparent Democratic unity gives the measure a more realistic chance of passing the House, with a pair of isolationist Republicans having voted for it last time.With a 217 to 214 majority, House Speaker Mike Johnson (R-La.) can only afford one GOP defection on an otherwise party-line vote.That doesn't even factor in House Republican leadership's attendance concerns, including that members who lost their primaries or bids for higher office will stop showing up to vote.State of play: Four House Democrats — Reps. Henry Cuellar (D-Texas), Jared Golden (D-Maine), Greg Landsman (D-Ohio) and Juan Vargas (D-Calif.) — broke ranks with their party leadership and voted against a resolution to immediately end the conflict in Iran earlier this month. The measure was otherwise universally supported by House Democrats, with Minority Leader Hakeem Jeffries (D-N.Y.), Foreign Affairs committee ranking member Greg Meeks (D-N.Y.) and other top Democrats whipping colleagues in favor of it behind closed doors.The four Democratic defectors, several of whom said they didn't want to undermine U.S. operations in the region, were subject to intense criticism from the party's grassroots.As the conflict in Iran has dragged on with growing confusion and collateral damage, Democratic opposition to it has only calcified.What they're saying: "It's time to finish the operation in Iran. It's time to be done. No expansion of the original operation. No ground troops," Landsman said in a statement last Friday.He added: "I will vote for Congressman Meeks' War Powers Resolution if it comes to the floor. I urge every one of my colleagues to vote Yes."A spokesperson for Rep. Henry Cuellar (D-Texas) declined to say how he will vote but pointed Axios to an alternative war powers resolution he supported that would have given the administration until March 30 — just six days from now — to wind down the war. A spokesperson for Golden declined to comment, and a spokesperson for Vargas did not immediately respond to a request for comment.What we're hearing: A senior House Democrat and another Democrat familiar with the matter told Axios that most, if not all, of the four defectors are expected to flip and vote for the measure this time.The second lawmaker, asked if all House Democrats will vote for the measure, told Axios: "Probably yes. One may vote no, but I think yes."That lawmaker, like several others quoted in this story, spoke on the condition of anonymity to speak candidly about sensitive internal dynamics.What to watch: Despite speculation to the contrary, House Democrats are not expected to force a war powers vote this week, a second senior House Democrat told Axios.The House will be on recess for the next two weeks, meaning the earliest a vote will happen is after the House returns on April 14.Jeffries said at a Tuesday press conference he is in "ongoing conversations" with Meeks and other committee ranking members about "moving forward with the war powers resolution sooner rather than later."