When veteran Massachusetts Democratic pol Ed Markey takes the oath of office as a U.S. senator today, it will represent a victory for liberal constituencies that recently have had a hard time achieving one: environmentalists, labor unions, reproductive rights groups — and President Barack Obama.

Along with lawyers and telecommunications interests, they all dug deep to help the longtime House member win a promotion to the upper chamber of Congress in a special election last month. 

Fear of another upset in the normally deep blue Bay State — like the one that in 2010 put Republican Scott Brown (temporarily) into the seat that the late Sen. Edward Kennedy, D-Mass., occupied for 47 years — sent some big Democratic donors into overdrive.

Chief mong them: The League of Conservation Voters, the SEIU and the environmentalist NextGen Committee.

Outside spending

What first appeared to be a sure pickup for Democrats escalated into a heated struggle between the Markey and his Republican challenger, political rookie Gabriel Gomez. Left-leaning groups poured money into the race in the hopes of avoiding another Republican upset à la Brown. A review of Sunlight's Follow the Unlimited Money records shows that Markey's top three supporters combined to spend almost $2 million on the special election. In total, outside groups invested $2.2 million on Markey.

The congressman, who ended up winning his race by a comfortable 10-point margin, on Monday completed a 37-year tenure in the House, where, most recently, he was the top ranking Democrat on the powerful Natural Resources Committee. Markey headed the select committee on climate change from 2006 until it was disbanded following the Republican takeover of the House. He has become a darling of environmentalist groups for his vocal support of alternative energy and role as co-sponsor of the American Clean Energy and Security Act of 2009 (which failed to clear the Senate).

The veteran congressman earned the endorsement of the LCV in January — before many would-be challengers had even announced their candidacy. All told, the group spent over $1.1 million on the special election through its super PAC and 501(c)4.

Markey also benefited from the financial muscle of California billionaire and environmentalist Tom Steyer. In spite of the congressman's pleas for Steyer to stay on the sidelines (part of an effort to keep outside money out of the race), the wealthy businessman's NextGen Committee spent more than $1 million during the primary and general election. In the primary, Steyer opposed to Rep. Stephen Lynch, D-Mass., because of Lynch's support of the Keystone XL pipeline.

Planned Parenthood also threw its support behind the Bay State liberal, spending over $145,000 in the cycle.

Famous faces and cold hard cash

While Markey clearly dominated the battle in outside spending, a review of his fundraising events shows that Democrats were not willing to leave anything to chance. President Barack Obama, as well his wife, first lady Michelle Obama, and musician Carole King all spent time stumping for the Senate contender.

Additionally, a review of Markey's Political Party Time records suggests that he benefited from the fundraising connections he has acquired in his nearly three decades of experience on Capitol Hill. From a party at the Massachusetts home of Walt Disney executive Alan Horn, to a Washington funder co-hosted by the Editor-in-Chief of Washington Life Magazine, Nancy Bagley, Markey has shown himself to be a serious force on the fundraising scene. 

The FEC's itemized list of campaign contributions to the official Markey's campaign committee shows significant contributions to his campaign war chest from cable and internet service providers, including $20,000 from the American Cable Association's PAC, as well as $10,000 from Comcast. Markey for years served as the top Democrat on a powerful House telecommunications subcommittee

As in years past, law firms remain a major source of Markey's campaign funds. Edwards Wildman Palmer's PAC chipped in $10,000 while the new Senator also received contributions from Washington heavyweights Covington Burling and DLA Piper.

Markey will fill the seat left vacant by John Kerry, who left the Senate in January to become secretary of state.

(Photo credit: Wikimedia Commons)