Hillary Clinton’s decision to switch jobs started a chain of events that doubled the number of U.S. senators who have signed a promise to protect the Internet.

Ed Markey (D-Mass.) was sworn into the Senate Tuesday after a 33-year career in the House. He fills the seat previously held by John Kerry, who in turn became U.S. Secretary of State after Hillary Clinton stepped down from that position in February.

Markey joins Senator Ron Wyden (D-Ore.) as the only members of the Senate to have signed the Declaration of Internet Freedom, that short, activist-drafted pledge to back principles like free expression, access, and privacy online.

It's fighting for that last point where Markey has shone of late. In 2012, Markey led a House committee to compel nine data-mining firms to come clean about their habits of tracking people's data to package and sell to other companies.

He's also introduced bills to regulate cell phone companies' ability to track their users and to limit the surveillance that unmanned drones can conduct.

Markey has been outspoken about former NSA contractor Edward Snowden's leaked revelations of vast agency spying programs to track Americans' phone records, saying he has "serious concerns" about such programs. He added, in a statement:

"As we look for the guilty needle, we can't invade the privacy of those in the innocent haystack. I have serious concerns about this program, and will continue my work to protect the privacy of individuals from excessive requests for wireless records and information."

Meanwhile, the Senate is still waiting to address a sweeping bill authored by Patrick Leahy (D-Vt.) to grant Americans more privacy protections from their own government's surveillance practices.

Photo via Ed Markey/Facebook