In the body of nearly every Associated Press wire report involving the United States and Iran, you'll find some version of this:
The two countries have not had diplomatic relations since the 1979 Islamic Revolution and the hostage-taking at the U.S. Embassy in Tehran. 
That editorial statement provides the historical backdrop for AP's U.S.-Iran reportage. Like many of AP's historical accounts, it is a parody of the actual record.
The events of 1979 are trumpeted to the exclusion of all others before and since, implying that Iran must atone for the past. But the 1979 Revolution was a response to the U.S. government's own anti-Iranian revolution and hostage-taking of 1953 and the subsequent 26-year rule of the U.S.-installed Shah, Mohammad Reza Pahlavi. AP naturally avoids editorial description of the U.S.-subsidized Shah's reign. 
To successfully cast Iran as the perpetual aggressor, AP must also omit all post-'79 U.S. aggressions against Iran, such as: the arming (including WMDs) and otherwise facilitating of Saddam Hussein for his 1980–88 aggressive war on Iran; direct U.S. military aggression against Iranian targets toward the end of that war (including the 1988 massacre of all 290 passengers and flight crew aboard Iranian Air Flight 655, by guided missile, over Iranian waters); the ongoing, taxpayer-looted funding of regime-change in Iran (including media propaganda and covert military operations); and the ongoing, liberty- and prosperity-destroying economic sanctions.
All of those are illicit acts of war, but according to AP they never happened.
All told, AP discards about 90% of the conflict timeline to put the onus squarely on Iran.
Omitted: US Constitution and Algiers Accords
According to state-worshiping news media (a.k.a., "MSM"), the U.S. government is worth its weight in good intention, no matter how "ineffective" its policies. How do AP editors pull this illusion off? Simple. Just conceal the most authoritative legal restraints on central power found in the plain and explicit language of the U.S. Constitution.
But there is another, less-referenced document whose plain language discourages certain propaganda mills from being intellectually honest with their readers. Signed by the United States and Iran, the 1981 Algiers Accords (.pdf), from the top, declares:
[T]he United States will restore the financial position of Iran, in so far as possible, to that which existed prior to November 14, 1979. . . .
The United States pledges that it is and from now on will be the policy of the United States not to intervene, directly or indirectly, politically or militarily, in Iran's internal affairs.
AP's account recalls zero U.S.-Iran diplomacy "since the 1979 Islamic Revolution and the hostage-taking at the U.S. Embassy in Tehran." But the '81 Accords was the very document that made the hostages' release official and sought to normalize relations. You might think it took some diplomacy to reach agreement there.
But once again, for AP it is simple: conceal the existence of not only illicit U.S. intervention in Iranian affairs, but the legal restraints thereon, and you are easily able to frame every Iranian response to unprecedented U.S. aggression as being unprecedented aggression itself.
Of course, if U.S. officials had simply fulfilled their oaths to preserve and defend the Constitution these last 60 years, there would've been no need for the Algiers Accords, and no major U.S.-Iranian row would exist today.
But you won't know this if you get your news from the New York Times, AP, NBC, and the like. Their unspoken duty is to frame a narrative around an innocuous U.S. government so that ill-informed and illicit U.S. interventions, to which — surprise! — statist media are rarely averse, are received with shallow disagreement if not "patriotic" support.
—————1. The Associated Press via Yahoo! News.
2. An occasional report will mention the violent overthrow of the "pro-US" Shah by "hard-line" Iranian students, as if the pillaging of the average Iranian under the Shah's regime was non-violent and moderate. One should wonder how AP defines pro-US.