Founder of ConsenSys: The SEC classifies Ethereum as a security at will without legal authorization

Joseph Lubin, co-founder of Ethereum and founder and CEO of ConsenSys, said in an article "Ethereum and Blockchain Technology Threatened by Washington Regulators" that without legal authorization, the Securities Exchange Commission (SEC) is reclassifying Ethereum from a commodity to a security at will in order to be able to enforce registration and other requirements related to securities within its jurisdiction, such as bonds, stocks, and other investments.
But Ethereum is clearly and logically not a security. On multiple occasions, the Securities Exchange Commission and the Commodity Futures Trading Commission have confirmed this, and ConsenSys' entire business model is based on this clear, prior regulatory consensus.
The Securities Exchange Commission's regulatory escalation violates the fundamental principle of separation of powers, according to which Congress is tasked with legislating and assigning jurisdiction over blockchains such as Ethereum.
More broadly, if the Securities Exchange Commission wins, it would mean the end of the Ethereum blockchain in the United States, as it makes Ethereum functionally inaccessible and unusable.