President Joe Biden is under increasing pressure to retaliate against Iran following an attack by Iran-backed militias that killed three US soldiers and wounded 34.

US troops in Iraq and Syria have been facing constant missile and drone strikes since last October when Israel began its onslaught on Gaza in response to Hamas’ rampage of the Israeli border communities. This is the first time, however, that such strikes have resulted in loss of American life – which many in Washington consider to be a red line.

The loss of life, after repeated warnings by his Iran policy critics, has left Biden with very little option but to escalate.

Biden and Secretary of Defense Lloyd Austin vowed Sunday evening to “hold all those responsible to account,” pointing out in clear terms who they had in mind. “We know it was carried out by radical Iran-backed militant groups operating in Syria and Iraq,” Biden said.

Tehran claimed innocence almost immediately, continuing its policy of 'plausible deniability.' “Iran has nothing to do with these attacks,” Iran’s official news agency IRNA quoted the country’s UN representative as saying. “The hostilities are between the US army and the resistance forces in the region that are engaged in tit-for-tat attacks.“

This message is unlikely to be taken seriously at the Pentagon or the White House, though, where, according to various reports, top level deliberations were underway Sunday evening to decide on an appropriate response.

But what would that response be?

“Washington could sink the Iranian navy, like then President Ronald Reagan did in the 1980s,” wrote Matthew Kroenig, vice president of the Atlantic Council. “It could strike Iranian naval bases. It could target Iranian leadership, following in the footsteps of then President Donald Trump’s killing of Iranian General Qassem Soleimani.”

That is in fact the incident many cite to argue that Biden’s fear of Iran’s retaliation is unfounded, since, the argument goes, the regime’s “hard revenge” for Soleimani was no more than a missile strike on a US base with enough notice for the personnel to evacuate.

A more controversial, and perhaps less likely, response could be to target Iran’s “nuclear and missile program,” Kroenig suggested, “which must be addressed soon regardless, as the Pentagon estimates its nuclear breakout timeline to be only twelve days.”

Any such scenario, and many more being discussed in US media, would be harsher than what President Biden has ever countenanced. But it has been that very unwillingness to be tough, his critics say, that has led to the loss of American life –and to this fateful moment for Biden’s political fortunes in an election year.

“The sorry truth is that these casualties are the result of the President’s policy choices,” reads the Wall Street Journal’s editorial Monday. “The President has put his anxieties about upsetting Iran and risking escalation above his duty to defend U.S. soldiers abroad.”

This is perhaps as harsh a criticism as a US President can get. And yet it's become so strikingly commonplace in Joe Biden’s case.

Questions are also being asked as to why the air defense systems at the US base (T-22 in northeast Jordan, bordering Syria) did not detect or shoot down the drone(s). According to the latest reports, 8 of the 34 injured soldiers have been airlifted to another country for treatment.

Any further loss of life could intensify pressures on the Biden administration to confront Iran directly, especially in an election year, with Donald Trump as the likely opponent, who, not surprisingly, is making the most of Biden’s predicament.

“Three years ago, Iran was weak, broke, and totally under control,” Trump said in a statement Sunday night. “Then Joe Biden came in and gave Iran billions of dollars, which the Regime has used to spread bloodshed and carnage throughout the Middle East. This attack would NEVER have happened if I was President, not even a chance.”

Many other Republicans also attacked Biden and his team for “appeasing” the regime in Iran and allowing it to undermine American interests in the Middle East undeterred.

“The only answer to these attacks must be devastating military retaliation against Iran’s terrorist forces,” Senator Tom Cotton said in a statement. “Anything less will confirm Joe Biden as a coward.”.

Many other GOP heavyweights joined in on the attack on the President , including minority leader Senator Mitch McConnell, the Armed Service Committee member Senator Rick Scott, and the committee’s Ranking Member Senator Roger Wicker.

“We must respond to these repeated attacks by Iran and its proxies by striking directly against Iranian targets and its leadership,” Wicker posted on X. “The Biden administration's responses thus far have only invited more attacks. It is time to act swiftly and decisively for the whole world to see.”

Some Democrats also called for action, in a clear sign of the hardening of moods on the Capitol.

“Every single malignant actor responsible must be held accountable,” the House minority leader Hakeem Jeffries wrote on X.

President Biden has said that the United State would retaliate at a time and in a way that it sees fit. If the mood in Washington is any indication, the response should be hard and delivered early.