On the Tripwire of a ‘Red Line,’ It’s Often Presidents Who Trip

When President Biden declared over the weekend that he was drawing a “red line” for Israel’s military action in Gaza, he appeared to be trying to raise the potential cost for Prime Minister Benjamin Netanyahu as their relationship plummets to new depths.

But he never said what would happen, exactly, if Mr. Netanyahu ignored him and continued Israel’s military operation by invading the southern city Rafah, a step that Mr. Biden has said — repeatedly — would be a major mistake. It is unclear whether he hesitated because he did not want to signal what response he might be preparing, or because he did not want to be criticized if he backed away from whatever action he is contemplating.

Or perhaps, given his long experience in the Senate and the White House, he remembered that drawing red lines turned out badly for Barack Obama when it came to Syria, and for George W. Bush when it came to North Korea and Iran. American allies in the Middle East were stunned by Mr. Obama’s reversal. Mr. Bush was later judged to have invaded a country that had no nuclear weapons — Iraq — while the North tested its first nuclear weapon on his watch.

Mr. Biden’s line-drawing was immediately dismissed — and matched — by Mr. Netanyahu, who shot back: “You know, I have a red line. You know what the red line is? That Oct. 7 doesn’t happen again.” The prime minister was referring, of course, to the Hamas attack that killed 1,200 people in Israel, left scores more as hostages and precipitated a war now in its sixth month.

Such talk of red lines is hardly new: Leaders of all stripes, from heads of democracies to vicious autocrats, often invoke the phrase to describe moves that another country should not even contemplate, because the consequences would be more painful than they could imagine. The odd thing in this case is that the lines are being drawn by two allies who regularly celebrate how close they are but whose dialogue has begun to turn somewhat poisonous.

The seemingly obvious implication of Mr. Biden’s threat was that if the Israelis went ahead with their plans and conducted another military operation with high civilian casualties, Mr. Biden would for the first time place restrictions on how Israel could make use of the arms the United States is supplying. Until now, Mr. Biden has rejected any such move — even though Washington places conditions on almost every arms sale, including requiring a commitment from Ukraine that it will not fire American missiles, artillery or drones into Russia.

But Mr. Biden appears to be slowly reconsidering his aversion to limits on how Israel could use the weaponry it buys, some American officials say. He has made no decisions, and still seems to be debating the question in his own mind, according to officials who have spoken with him.

In public, the White House will not discuss the subject. At a briefing with reporters on Air Force One on Monday, as Mr. Biden headed to New Hampshire for a campaign event, a White House spokesman refused to say what price Israel would pay if it crossed Mr. Biden’s red line. And Mr. Biden himself ruled out cutting off any defensive weapons, like Iron Dome, the U.S.-Israeli missile defense project that has intercepted short-range missiles shot into Israel by Hamas.

“It is a red line, but I am never going to leave Israel,” he said in an interview with MSNBC last week. “The defense of Israel is still critical. So there is no red line I am going to cut off all weapons, so they don’t have the Iron Dome to protect them.”

“But there’s red lines that if he crosses,” he added, drifting off from completing the sentence — or the threat. “You cannot have 30,000 more Palestinians dead.”

In using the red-line wording, with its vivid suggestion of some kind of tripwire, Mr. Biden was also wading into dangerous territory for American presidents. Time and again in the past few decades, Mr. Biden’s predecessors have described limits that America’s adversaries or allies could not step over without invoking the most severe consequences.

And time and again, they have come to regret it.

Take Mr. Obama’s declaration in August 2012 when intelligence reports suggested that President Bashar al-Assad of Syria might be preparing to use chemical weapons against his own people. Mr. Obama had steered clear of Syria’s internal upheavals, but one day in the White House press room he told reporters that if Mr. Assad moved or used large quantities of chemical weapons, he would cross a “red line” and “change my calculus.”

By the spring of 2013, it was clear that Mr. Assad was doing exactly that, and when a senior Israeli intelligence official declared as much, the Israeli government had to back away from the comments, for fear that the intelligence finding would box Mr. Obama in. By the early summer, it was becoming clear that the weapons were in active use, but Mr. Obama called off a planned strike on Mr. Assad’s facilities, worried that it could prompt even more chemical attacks — and suck the United States into another major conflict in the Middle East.

Mr. Bush found himself in a similar situation in 2003 when he declared that he would not “tolerate” a nuclear-armed North Korea. That summer he used the same word to say he would not put up with Iran’s obtaining the capability to build a nuclear weapon.

During his presidency, the North Koreans tested a nuclear weapon — they have since tested five more — and the Iranians made progress toward that capability. And while the United States has ratcheted up sanctions and threatened military action with both, the North has such a substantial arsenal now that American officials have all but given up the idea that it will ever disarm.

Iran’s capability — which seemed neutered, at least for a while, after Mr. Obama struck a nuclear deal in 2015 — has surged back since President Donald J. Trump abandoned that deal three years later. Today, it has a stockpile of enriched uranium that could be converted into weapons-grade fuel in days or weeks, and a weapon within a year or so.