Now that the United States has implicated the Islamic Republic of Iran in a plot to attack targets in Washington, the Obama administration must determine how to respond.
President Obama made outreach to Iran the center piece of his foreign policy.
"We will extend a hand if you are willing to unclench your fist," he declared at his inauguration.
Twice he wrote letters to Iran's Supreme Leader and, even after getting swatted down twice, the White House held out hope.
While the Iranian plot on America should end that hope, diplomats never say never.
Proponents of dialogue will argue that there is no evidence that the Iranian government was aware of the plot, and that the Revolutionary Guards' elite Qods Force was a rogue operator.
The Iranian government thrives on plausible deniability, but no longer should the White House allow Tehran to get away with it.
The Supreme Leader is a dictator, but unlike Saddam Hussein or Kim Jong-il, he does not give orders as much as he wields ultimate veto power.
He will turn off any plot he disapproves of, and only allow those for which he approves to move forward.
For American intelligence analysts, this means there will never be a smoking gun linking terrorism to Iran's top cleric.
Past behavior, however, sheds light on the present.
While diplomats have tried to dismiss past Iranian terrorism as the result of rogue agents, Iran's own promotion record suggests differently.
In 1989, Iranian gunmen mowed down a Kurdish dissident in Vienna. The ringleader returned to Tehran, where he received a promotion and became a general in the Qods Force.
In 1994, terrorists bombed the Jewish community center in Buenos Aires, killing 85. The leader of that plot is Iran's defense minister today.
The opposite is also true: When an elite revolutionary squad kidnapped the Syrian ambassador without permission, it was the group's leader who faced the firing squad, not the Syrian.
Diplomacy must be based on reality, not on wishful thinking.
The terror plot was no rogue action. Obama may hold an olive branch, but the White House must recognize the Iranian regime's fist holds only blood.
The time for talk has ended.