Markey, a longtime Democratic congressman, will be the heavy favorite in a special election to replace John Kerry.
The insurance overhaul, which turns three Friday, carried Republicans to huge gains in 2010 but wasn't a major factor in 2012. Is it poised to claim new victims?
The longtime senator's decision opens the field up for potential successors -- and could offer Republicans a chance to pick up a seat.
National Journal's annual ratings of House and Senate members show the body was more polarized than ever in 2012, but there are reasons not to despair in 2013.
The Republican, who lost in November, declined to run his third Senate race in four years, leaving the GOP nomination wide open and boosting Democratic chances.
In rejecting a Montana law barring corporate contributions, the Justices reaffirm Citizens United and shows reformers' bleak prospects.
Frictionless, quick, easy -- getting donors to give using their phones could be a boon for the presidential campaigns.
Why is the president trying so hard to split hairs in his Bain attacks? Just look at where the campaign cash is going.
The decision, in a swing state the president hopes to win again, shows how the issue can split the Democratic coalition and endanger his reelection.
Ceding a potentially losing fight over the Bin Laden death, the Republican turns to President Obama's greatest vulnerability.
With even many of his supporters admitting, he's finished, how will Santorum campaign from here -- and why?
Even though his father, mother, and brother have backed the front-runner, he remains too toxic to be sought after.
His backing won't force Santorum and Gingrich out immediately, but it cements the idea of Mitt Romney's inevitable nomination.
When it comes to attacking Mitt Romney, Santorum seems to be reading from the same playbook as the Obama re-election campaign.
A notion ridiculed a few short weeks ago is now becoming more plausible -- even if it's not yet a likely outcome.
Many voters love Rick Santorum's positions, but they're ready to settle for Romney's superior organization and presumed electability.
As expected, the former Massachusetts governor easily captured the Grand Canyon state's 29 delegates.
A Santorum victory would be bad news for the Republican Party, but the road ahead will remain rocky even if Romney ekes out a win.
The presidential candidate says he wants to take "counteraction" against Beijing for its trade policies, but U.S. China-hands are skeptical.