America's on-again, off-again business blockades against Iran weigh heavily on Western companies that plan to do business in that nation of 82 million, best known abroad for exporting petroleum to Europe.

Consider SAP SE, the German business-software giant, whose U.S. headquarters and global CEO, Bill McDermott, are based in Newtown Square.

When the United States joined Germany, Britain, and France in lifting financial sanctions against Iran in 2016, following that country's agreement to cut back its nuclear development program, SAP was among the European software makers whose services Iranian employers sought in hopes of joining the digital age, following years of Western boycotts.

Butane Industrial Group, an Iranian energy company, advertised on LinkedIn for staff to implement SAP systems
Butane Industrial Group, an Iranian energy company, advertised on LinkedIn for staff to implement SAP systems

Mammut Systems, based in the Iranian capital of Tehran, announced plans to implement SAP's enterprise resource planning (ERP) systems at Iranian employers. Butane Industrial Group, a Tehran energy company, advertised for its own SAP ERP implementation staff.

Even when trade opportunities open, this can be a tough part of the world for Western companies to do business while complying with Western laws and policies. Last year, Tayfun Topkoc, the Turkey native who headed SAP's Persian Gulf business since 2014, resigned after SAP said it was launching an investigation into its sales practices in the region. Reuters reported the investigation centered on SAP sales in Iran. The disclosure came at an embarrassing time, following SAP's replacement of its South African leadership in a corruption probe.

Separately, Boeing, the aircraft maker that builds helicopters in Ridley Township, Delaware County, partnered with its European rival, Airbus, in an agreement to sell modern passenger jets to Iran Air, a set of deals worth $40 billion.

And Western energy companies had resumed weighing possible investments in Iran's large but antiquated fuel industries — even as the hope of improved trade pushed the price of oil so low that the economy of Iran, as in Russia, Venezuela, and other petroleum exporting countries whose policies are also at odds with the U.S., stalled from the decline in energy-sales income.

Those business interests and the hope of shareholder profits from Iran trade have gone behind the clouds following President Trump's announcement Tuesday that he will make good on his campaign promise to reimpose economic sanctions on Iran.

"German companies doing business in Iran should wind down operations immediately," Trump's new ambassador to Germany, Richard Grenell, a former George W. Bush aide, Harvard graduate, and Fox News commentator, said in a statement on social media.

Grenell was promptly scolded by Germany's ruling conservative and opposition liberal parties for trying to push that nation's private sector around. But Wednesday, when I asked SAP about the impact of Trump's action, spokesman Andrew Kendzie was careful to note that SAP itself "does not conduct business in Iran.  Any use of SAP software in Iran is unauthorized and contrary to SAP license and end-user agreements." He said the company had previously told Mammut that SAP "does not authorize the sale or support of SAP products in Iran."

Trump's Iran move also "slammed shut what had been a brief opening for aircraft sales by Boeing" and Airbus, including Airbus' U.S. suppliers such as General Electric and United Technologies, as well as Germany's Siemens, Bloomberg News reported.

The move looks worse for Airbus, which had booked nearly 100 jet sales to Iran, than it does for Boeing, which since Trump's election had "quietly lined up other customers for some of the 777-300ER jetliners once intended for Iran Air," Bloomberg added.

Renewed U.S. sanctions "will not directly affect Iran's ability to produce and sell its crude" oil, wrote energy analyst Pavel Molchanov, in a report to clients of Raymond James and Associates. "The U.S. ban on importing Iranian crude had never been lifted, and U.S. companies are not directly involved in Iran's energy sector."

And yet, "oil prices set fresh four-year highs this week" in anticipation of Trump's move, with Pennsylvania gas prices rising above $3 a gallon. Fuel prices could go higher if America's European and Asian allies stop buying Iranian crude for fear their companies will otherwise be punished by the U.S., according to Molchanov.

Molchanov added that he's more concerned about instability in oil producer Venezuela, which faces what could be a violent presidential election on May 20, as the beleaguered socialist government of Nicolas Maduro hopes to stay in power long enough to benefit from the new rise in the price of oil.