The 112th US Congress convened this week with a new Republican majority in the House of Representatives, a new speaker, John Boehner from Ohio and a series of new representatives.
US President Barack Obama's Republican foes formally took control of the House after routing the White House's Democratic allies in November 2 elections.
Here are some Republican lawmakers to watch as power-sharing in Washington sparks bitter feuding and uneasy efforts to compromise in the short span before the 2012 presidential race gets under way in earnest.

- House Speaker John Boehner

Boehner, who has by turns been congressional bomb-thrower and bridge-builder throughout his two decades in Washington, will now be the sharpest thorn in Obama's side, with sweeping control over the House's legislative agenda.
The lawmaker, who hails from the critical swing state of Ohio, will likely have to harness his considerable deal-making skills to enact key planks of the Republican agenda in the face of opposition from the Democratic-run Senate. But Boehner, who replaced Democrat Nancy Pelosi, will have to find ways to satisfy archconservative "Tea Party" activists who powered the Republican election gains.

- House Majority Leader Eric Cantor

Cantor (Rep. Virginia), the first Jewish Republican to hold the post, kept Republicans in near-lockstep opposition to Obama's agenda since the president took office in January 2009, denying him any sizeable bipartisan support on key issues.
He will play a pivotal role as House Republicans forge ahead with their pledges to slash spending, lift what they call "job-killing" government regulation, and look to rein in Obama's agenda.

- House Foreign Affairs Committee Chair Ileana Ros-Lehtinen

The Cuban-born lawmaker from Florida, already a key Republican foreign-policy voice, has vowed a region-by-region, country-by-country, program-by-program review of diplomatic and foreign aid programs for spending cuts.
She is also expected to challenge Obama to take a harder line on issues like Iran's nuclear program, the government of Venezuelan President Hugo Chavez and Russia's rights record.

- House Oversight Committee Chairman Darrell Issa

Issa, who made a fortune in the car-alarm business, relishes his new role as the Obama administration's chief inquisitor and plans investigations into the Wikileaks controversy, Afghan corruption, the US housing collapse, and government oversight of food safety.
The California lawmaker has drawn Democratic fire for writing a letter to more than 150 trade associations and companies including Toyota and Bayer asking them to identify burdensome regulations that hamper job creation.

- The "Tea Party" Representatives

They don't have an official leader, official headquarters, or even a formal platform, but these arch-conservative activists fueled the big Republican gains in November and now expect the party to heed their demands to slash goverment spending, scrap regulations, and assail Obama's signature health care overhaul.
But at least one prominent Republican leader has already warned against partisan overreach that could alienate independent voters and pave the way to a second term for Obama, and others have counseled patience and compromise in the face of a Democratic Senate and an override-proof presidential veto.