Envelopes containing powder come weeks before midterms as federal agents try to identify who is behind campaign

More than three dozen members of the US Congress have had their offices targeted with envelopes containing white powder, less than three weeks before the 3 November midterms, as federal agents try to identify who is behind them.

The latest is the Virginia Democrat Suhas Subramanyam, whose Leesburg district office was evacuated on Monday after an envelope containing a suspicious substance arrived. He said the office was cleared quickly, adding that “acts of political intimidation have no place in our country”.

As the midterm elections loom, Oliver Laughland and Tom Silverstone travel to rural West Virginia, a Republican party stronghold, to explore how soaring gas prices, war in the Middle East and datacenter expansion are affecting Donald Trump's popularity among his base. Although the state remains staunchly Republican, there are signs of a new politics emerging – and local Democrats are looking to capitalize on it