Last week, I joined my colleagues in voting for the conference agreement to the Comprehensive Iran Sanctions, Accountability, and Divestment Act. The Senate and House both passed the finalized bill, which will now go to the President to be signed into law. While I remain concerned about the efficacy of using sanctions alone to bring about change in Iran, I hope this measure will spell the beginning- not the end-of a new, constructive engagement with Iran.

This legislation is the latest in more than two decades of efforts to pressure Iran though trade embargoes and other economic penalties. In 1984, we added the country to our list of state sponsors of terrorism, which directs the government to cut off all economic aid. Eleven years later, President Clinton signed an executive order banning direct investment and trade with Iran. The measure builds upon these previous efforts by banning U.S. financial institutions from using their foreign subsidiaries or foreign banks to do business with Iran. The bill also imposes sanctions on any foreign company that assists Iran in the development of its energy sector; from insurance companies that deal with Iran’s domestic refining efforts, to shipping firms that assist in the transport of petroleum.

The Comprehensive Iran Sanctions, Accountability, and Divestment Act sends a clear message from the U.S. to the Iranian government that we are not bluffing. At the same time, this bill signals our concern for the Iranian people by ensuring that our sanctions do not infringe on the ability of private citizens to communicate and disseminate information, both key ingredients to building a strong civil society and affecting democratic progress.

To this end, the Comprehensive Iran Sanctions, Accountability, and Divestment Act includes a provision I authored to make it easier for the people of Iran to access US made internet communication software such as Twitter and Gmail. This will allow ordinary Iranians to share the stories of civil disobedience and state violence that were instrumental in the recent Green uprising. I thank Congressman Howard Berman for working with me to include this provision in the final bill, and in the future, I ask that my colleagues take further measures to promote freedom of expression for the Iranian people.

While Congress’ latest action was appropriate, focusing solely on sanctions will not bring a change in Iran’s government or the behavior of its leadership. Unless they are coupled with intense, comprehensive diplomacy, unilateral sanctions will simply bolster the Iranian government’s staying power. That is why it is so critical that America follow its recent actions on sanctions with an equally aggressive diplomatic campaign. While there is no guarantee of the success of diplomacy, we can be sure that the absence of it will only give Iran more room to continue pursuing nuclear capabilities.

Rep. James Moran (D) is Virginia’s 8th Congressional District Representative in the U.S. House of Representatives.