"The sanctions are nothing but gratuitous propaganda. Obama himself acknowledged that it is uncertain whether the additional sanctions will have any effect," Roberts told RIA Novosti. "Besides, the sanctions will encourage and hasten Russia's withdrawal from Washington's exploitative dollar payments system, and the BRICS countries are likely to follow."
US President Barack Obama levied the additional sanctions against Russia to target individuals and companies close to Russian President Vladimir Putin.
The sanctions were imposed on seven Russian government officials, as well as 17 companies.
"The Obama regime continues to pretend that a few Russian individuals and companies are responsible for Crimea's return to Russia," Roberts said, stressing that the evidence is completely clear that the return of Crimea to Russia was the result of the Crimean people and their self-determination.
"People voted 97 percent in an amazingly large voter turnout to return to Russia, from which Khrushchev detached Crimea in the 1950s," he explained.
Roberts foresees that the announced measures will only encourage the Russian government to withdraw from the dollar-based payment system that makes sanctions possible.
"It is a mystery to me why countries such as Russia and China participate in the dollar payments system, as the system is a means of US financial and political imperialism," the former assistant treasury secretary said. "No country that operates within Washington's payments system can have an independent policy."
He added that "Once important countries cease to use the US dollar as a reserve currency and the means of settling international payments, Washington's imperial power will decline."
Last Saturday, leaders of the G7 group of nations accused Russia of failing to comply with the Geneva communique aimed to de-escalate the crisis in Ukraine agreed by top diplomats from Russia, Ukraine, the United States and the European Union on April 17. The G7 members threatened Moscow with tougher sanctions.
On Monday, White House Press Secretary Jay Carney announced that the United States would impose broad sanctions against Russia's economic sectors if it launched a military incursion into Ukraine.
"The United States, working closely with its partners, remains prepared to impose still greater costs on Russia if the Russian leadership continues these provocations instead of de-escalating the situation, consistent with its Geneva commitments," Carney's statement on the White House official website reads.