Analysis Summary:

The article makes a broad claim about the US-Iran relationship being tested before, but this time being of greater magnitude. While the provided sources don't directly address this specific claim, they offer context about the region and past agreements with Iran. The lack of direct verification for the central claim impacts the factual accuracy score. There is a moderate level of bias due to the subjective nature of the claim and the potential for selective framing.

Detailed Analysis:

• Claim:** "The 'tortuous' US-Iran relationship was tested at least once before, but this is of far greater magnitude."
  • Verification Source #4: Discusses the Iran Deal, a past attempt to prevent Iran from acquiring nuclear weapons, suggesting a previous significant point in the US-Iran relationship.
  • Verification Source #5: Mentions a history-making moment, but not directly related to the US-Iran relationship.
• The claim is not directly verifiable by the provided sources. The sources provide context about past events involving Iran, but do not explicitly compare the magnitude of the current situation to previous ones.
• Internal Knowledge:* The US and Iran have had a complex and often adversarial relationship for decades, with events like the Iran hostage crisis, the Iran-Iraq war, and the development of Iran's nuclear program representing significant points of tension. Without more context from the article, it's difficult to assess the accuracy of the "far greater magnitude" claim.

Supporting Evidence/Contradictions:

• Verification Source #4: Provides evidence of a past significant event in the US-Iran relationship (the Iran Deal). This supports the idea that the relationship has been "tested" before.
• The provided sources do not directly contradict the claim, but they also do not offer direct support. The claim's accuracy is therefore uncertain based on the available information.