The US decision to impose a second round of sanctions against Russia over the Skripal poisoning was the result of pressure by powerful forces in the US which are against the normalisation of relations with Russia for political domestic reasons, and because US elections are approaching, while Trump seeks instead to improve relations with Russia.
Conspiracy theory; no evidence given. One of many recurring pro-Kremlin narratives about the Skripal poisoning claiming that allegations of Russian responsibility for the attack are fueled by Russophobia or by anti-Russian provocations and conspiracies.
US President Donald Trump signed an executive order on August 1, 2019 imposing a second set of sanctions against Moscow - as mandated by the 1991 Chemical and Biological Weapons Control and Warfare Elimination Act (CBW Act) - for its use of a Novichok nerve agent in an attempt to assassinate Sergey Skripal and his daughter.
The United States imposed the first round of sanctions on Russia in August 2018, with a 90-day deadline for Russia to give "reliable assurance" that it would no longer use chemical weapons to escape a second round. The CBW act mandated the imposition of new sanctions within 90 days if Russia failed to give such reliable assurance.
UK police and intelligence investigations have produced hard evidence of Russia's involvement in Skripal poisoning, sufficient to charge two Russian nationals – identified as officers of the Russian Military Intelligence (GRU) – for the attack on the Skripals.
Furthermore, the UK investigation found that Sergey and Yuliya Skripal were poisoned using a specific Novichok nerve agent that cannot have been produced by non-state actors. This was confirmed by an independent OPCW [Organisation for the Prohibition of Chemical Weapons] analysis.
According to the UK intelligence assessment, based on open-source analysis and intelligence information, in the past decade Russia has produced and stockpiled small quantities of Novichok agents, long after it signed the Chemical Weapons Convention.