As the end of 2013 approaches, the Washington Examiner is taking a look back at the biggest stories and issues of the year. Today, it's political campaigns.

The next presidential election seems far away, but potential candidates, including Republicans Ted Cruz and Rand Paul and Democrat Elizabeth Warren, are already making waves. Meanwhile, differing factions within the GOP prepared to duke it out in 2014 congressional primaries, and Obamacare's poor rollout created an opportunity for Republicans to pick up control of the Senate.

Here are some of the top Examiner stories of 2013 on campaigns:

The Establishment fights back: Mitch McConnell leads GOP's battle against Tea Party insurgents

By David M. Drucker, Dec. 4

In the wake of the government shutdown, the Senate minority leader began leading an Establishment push-back against the Senate Conservatives Fund and other groups pushing the GOP in a direction that concerns McConnell.

McConnell worries that the Senate Conservatives Fund and other insurgent groups are pursuing a confrontational, uncompromising strategy that makes it impossible for conservatives to govern.

“The Senate Conservatives Fund is giving conservatism a bad name. They’re participating in ruining the [Republican] brand,” McConnell said. “What they do is mislead their donors into believing the reason that we can’t get as good an outcome as we’d like to get is not because of a Democratic Senate and a Democratic president, but because Republicans are insufficiently committed to the cause — which is utter nonsense.”

The outside groups, in McConnell's view, are unaccountable and financially motivated and pose a threat to the Republican Party's viability. The groups in 2010 and 2012 backed a handful of untested, ideological candidates in Republican primaries that couldn't win general elections, costing the party opportunities to build a majority. It's a threat that must be addressed ahead of the 2014 and 2016 elections, McConnell said, because it's repelling the very voters the GOP needs if it's ever to take control of the federal government.

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Rand Paul and Ted Cruz are not as similar as they look

By Rebecca Berg, Oct. 4

In the budget battles surrounding the October government shutdown and near-breach of the debt limit, two top 2016 candidates took divergent paths.

While Cruz fights over ideology, Paul leads a rising libertarian faction within the party. Cruz rallies activists outside the Beltway. Paul focuses on policy and earned a reputation in the Senate for working within the body’s traditional framework and with quiet consideration for colleagues. The tack earned him respect even from those who disagree with him, including Sen. Lindsey Graham, R-S.C.

Graham and many other conservatives view Cruz as a bull in a china shop, but they appreciate what's driving him.

“Ted’s new, he came here with a lot of passion, he was the underdog in a primary, he feels really beholden to the people that helped him in the primary, and I understand that,” Graham said.

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Ambivalent about Hillary, liberals cheer Elizabeth Warren

By Tim Mak, Dec. 6

The freshman Massachusetts Senator has repeatedly said she isn't running for president. But many Democrats who worry that presumptive front-runner Hillary Clinton would be beholden to Wall Street interests are pushing Warren to join the fray.

Warren has come to represent the Left’s aspirations for the next Democratic presidential nominee, and thousands have flocked to a Facebook page calling on Warren to run.

“Warren is viewed as the North Star of the Democratic Party, who the Democratic Party should look to for where to go in the future,” said Matt Wall, of the Progressive Change Campaign Committee. “We're a fan of Warren because she's a progressive champion, and is willing to stand up for progressive ideals.”

Wall's group is so enamored of Warren that it dispatches members to major Democratic Party events to promote her with shirts and stickers that read, “I’m from the Elizabeth Warren Wing of the Democratic Party.” The group's website is already selling Elizabeth Warren merchandise — including an Elizabeth Warren onesie for babies.

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Obamacare woes have GOP dreaming of a Senate majority

By Rebecca Berg, Dec. 13

As the president's signature achievement sputtered late in the year, Republicans began believing they could not only win battleground elections in Arkansas, Louisiana and North Carolina in 2014, but also challenge one-safe Democratic seats in Virginia, New Hampshire and Michigan.

Polls show that any advantage Democrats gained when voters blamed Republicans for a 16-day government shutdown in October has all but evaporated since the debut of Obamacare. A record number of Americans now consider the health care law to be bad for the country, and Republicans have grown optimistic that the icy reception will move enough votes in battleground states to give the GOP control of the Senate.

“In a midterm [election] where Obama will not be on the ballot himself, it’s his job, not his likability, that will have the most influence,” said Brook Hougesen, a spokeswoman for the National Republican Senatorial Committee.

Vulnerable Democratic incumbents are testing campaign messages about the health care law in light of its initial problems and subsequent attempts to fix it. Democratic Louisiana Sen. Mary Landrieu, an Obamacare supporter, ran her first television ad of the campaign criticizing the law."

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