WASHINGTON: Iran's downing of a US drone marks the latest escalation that has raised fears of all-out war - and, despite President Donald Trump's call for talks, there are few reasons to believe tensions will ease anytime soon.
The adversaries confirmed that Iran shot down a US spy drone, with Washington insisting it was in international waters over the strategic Strait of Hormuz but Tehran saying that the drone violated its airspace.
One point on which most agree is that the intensifying showdown is linked to Trump's "maximum pressure" campaign, in which the United States has sought to cripple Iran's economy and reduce its regional role.
Trump, who has repeatedly said he does not want war, offered mixed messages over the drone, warning that Iran "made a very big mistake" - but also suggesting a "loose and stupid" Iranian general accidentally shot it down.
Behnam Ben Taleblu, a senior fellow at the Foundation for Defense of Democracies, which advocates a hard line on Iran, said he expected further escalation by Tehran "until it is incentivised against doing so."
"Iran has likely calculated that America will not respond with anything other than sanctions - a proposition which may be true today, but could change over time if Iranian escalation is deemed particularly egregious," he said.
The United States has also blamed Iran for a series of attacks on oil tankers in the Middle East, although the clerical regime has denied responsibility.
Ben Taleblu said Iran has broader political goals with its actions but could back down faced with a tougher US stance or a "measured response."
"Escalation is also designed to raise the cost of persistence to the Trump administration and to tempt Washington into premature diplomacy and watered-down sanctions," he said.
DIM HOPES FOR TALKS
Trump, who had warned of wiping out North Korea before welcoming its leader Kim Jong Un to talks, has sent out repeated feelers to Iran in hopes of similarly jump-starting negotiations, diplomats say.
But Iran has rebuffed the overtures, refusing to negotiate with an administration that has gloated over the country's sanctions-triggered recession and walked away from a denuclearisation deal brokered after exhaustive talks under former president Barack Obama.
Ali Vaez, director of the Iran Project at the International Crisis Group, which looks for peaceful ways out of conflict, doubted Tehran would take Trump's offer of talks seriously "as long as he holds a gun to Iran's head."
Any US military response to the drone incident would trigger further retaliation, he said.
"But a disproportionate response will be an even graver mistake, as it could prompt a conflict that can easily spiral out of control," he said.
Vaez said the two countries could still find ways to step back from the brink including by establishing a hotline between their militaries.
Trump's Democratic rivals say Iran's actions were entirely predictable once Trump withdrew from the nuclear accord, with which UN inspectors say Tehran was complying.
"We're saying to Iran - we negotiated, you agreed, but we're breaking the deal and now we want to negotiate again," said Democratic Senator Jeff Merkley.
"People don't tend to want to negotiate with folks who have broken the previous deal," he said on the Senate floor, warning that "we stand on the precipice of potential war."
HARDLINERS ON BOTH SIDES
Iran by the end of the Obama administration enjoyed a recovering economy and its moderate government was engaged in regular contact with the United States, a startling turnaround after four decades of hostility following the overthrow of the pro-Western shah.
When Trump pulled out of the accord, Secretary of State Mike Pompeo set 12 demands for Iran that virtually no one believes it will meet, such as abandoning all its allies in the Middle East, where the United States has staunchly backed rival Saudi Arabia.
Colin Kahl, a former Obama aide now at Stanford University, recently published a scenario on how Iran and the United States could stumble into war, especially if Tehran feels the squeeze from unilateral US sanctions aimed at ending all its oil exports.
Kahl wrote on Twitter that Pompeo and hawkish national adviser John Bolton appeared to be "trying to box Trump in," with the more cautious Pentagon further marginalized with this week's departure of Patrick Shanahan as acting defense secretary.
"A key point is that if escalation happens, it won't be about the drone per se, but the preferences of hardliners on both sides," Kahl said.