For the last 22 years no US president had blocked a foreign firm from investing in the United States. Now Barack Obama is getting sued for doing just that, after he stopped a Chinese windfarm project in Oregon, citing "national security" concerns.

Why? Officially, because the privately held Ralls Corporation plans to purchase four small windfarms close to air space used by the US navy. (Ironically, the area is used for developing drones – robot weapons which make the US dangerous enemies across the world).

But other factors are clearly at play here. Jobs have become a key election issue: Republican candidate Mitt Romney has accused Obama of failing to protect US business against unfair competition from China; Obama in turn has claimed that Romney's firm Bain Capital has shipped US jobs overseas.

In this war of words, both candidates are falling over themselves to appear aggressively nationalist and, it would seem, anti-Chinese – with disastrous consequences. America's protectionist rhetoric and action is actively impeding the global fight against climate change. Already, the US has accused China of "dumping" cheap solar panels on the US market, and has moved to block them, sparking fears of a trade war and imperiling one of the key rays of hope for progress on climate change.

Ralls Corporation has accused Obama of overstepping his authority as president, and has added his name to its lawsuit against the treasury department's foreign investment committee. Legal experts think this case will be tough to win, but there's a lot more at stake here than just four windfarms in Oregon.

Sources: BBC, Guardian , White House, Avaaz, Politifact