(CNN) -- Voters head to the polls next November for midterm elections and there's a ton at stake: Possible shifts in control of the U.S. Senate and House and some very interesting gubernatorial races with potential national implications. There is also Hillary Clinton - what will she do about 2016? Ditto for Chris Christie and a bunch of other Republicans who may hold White House ambitions. What impact will Obamacare and the economy have on the electorate? Here's a rundown on the key political questions for 2014:
1). Can the GOP win back the Senate?
When it comes to controlling the Senate, Republicans hope the third time is the charm. The GOP narrowed the gap but failed to win it back in 2010 and actually lost ground two years later.
But with Democrats defending 21 of 35 seats up for grabs next November, including five of seven open races, the odds again look good for the GOP. It has to make a net gain of six seats to control the chamber for the first time since 2006.
The Rothenberg Political Report, a top non-partisan political handicapper, predicts a four- to seven-seat gain for Republicans.
And the Cook Political Report, another leading non-partisan handicapper, puts the GOP's chances of winning the majority at 25%-30%.
"On paper anyway, Democrats' challenges would appear to be a heavier burden than those faced by Republicans. Not only do they have to fight their battles in red states, but they also have to deal with a political landscape that could well produce a restless electorate," writes Jennifer Duffy, Cook Report senior political editor.
2). Do Democrats have a shot at the House?
This looks less likely than Republicans gaining control of the Senate. Democrats need to retake 17 GOP seats to win control for the first time since 2010.
Announcements this month that two longtime Republicans would retire at the end of 2014 have boosted Democratic hopes.
The GOP must defend eight of nine open races, but there are far fewer swing seats than in elections past due to redistricting.
Also, a traditionally older electorate in midterms tends to favor Republicans.
"Because the House is well sorted-out, large shifts or a change in partisan control of the House are unlikely. If the election were held today, we would estimate a Republican gain of between zero and 10 seats," writes David Wasserman, the Cook Report's House editor.
And Stuart Rothenberg, publisher and editor of the Rothenberg Report, says "a small net House gain for Republicans in 2014" is possible.
3). Will Democrats make state house gains?
A whopping three dozen gubernatorial contests are on tap in 2014 with Republicans defending 22 of them.
Some Republican governors in blue or purple states face a tough road to re-election, including Tom Corbett of Pennsylvania, Rick Scott of Florida, Rick Snyder of Michigan, and Paul LaPage of Maine.
And some potential 2016 Republican presidential hopefuls, such as Wisconsin's Scott Walker and Ohio's John Kasich, could also face challenging races.
Two Democratic incumbents, Connecticut's Dan Malloy and Pat Quinn of Illinois, also have their work cut out for them.
The races for governor could be more interesting than what happens in Washington.
4). Will GOP primary battles be costly come November?
Seven of the 12 Republican Senators up for re-election face primary challenges from the right. The list includes the top two Republicans: Minority Leader Mitch McConnell of Kentucky and Minority Whip John Cornyn of Texas.
Since the birth of the tea party in 2009, primary challenges from the right have made headlines and have hurt GOP efforts to win back the Senate.
"Republicans effectively gave away five Senate seats the last two cycles because of candidates who weren't capable of winning in November," said Brian Walsh, a Republican strategist and communications director in the 2010 and 2012 cycles for the National Republican Senatorial Committee, which provides support, advice and funding to Republican candidates.
But Walsh said he doesn't see a repeat because he rates many of the challenges as "not serious at this point."
A top Senate Democratic official disagreed.
"Primaries are forcing all Republican candidates to embrace the tea party and a slate of policy positions that will hurt them in a general election," said Matt Canter, deputy executive director of the rival Democratic Senatorial Campaign Committee.
5). Does Obama help or hurt his party in midterms?
There's no denying that 2013 was a tough year for President Barack Obama. And with an approval rating currently hovering in the low 40s in most national opinion polls, the question is: How will he impact Democrats in November?
"Obama's standing is likely to be a problem for Democratic Senate hopefuls unless his poll numbers recover noticeably. This holds for Democratic incumbents who seek to separate themselves from the President, as well as open-seat candidates and challengers," writes Rothenberg.
Midterm elections are often a referendum on a sitting president, so expect to see Obama's approval ratings in the spotlight right until the Election Day.
6). How will Obamacare impact Democrats?
The national health care law is the President's signature domestic achievement. The Affordable Care Act was a major issue in 2010 and 2012 and will likely be so again in 2014.
While Obamacare's disastrous rollout starting in October was a contributing factor behind the drop in Obama's poll numbers, things are starting to improve. Major flaws with the measure's website, HealthCare.gov, are being addressed and enrollment is gaining.
But the controversy over canceled policies due to Obamacare played into Republican hands. And Obama's inaccurate pledge that "if you like your insurance, you can keep it" under the new health law is a line that will show up repeatedly in GOP ads going forward.
Republicans have pledged to keep the campaign focus on the health care law even if it starts to gain traction with the public.
Because midterms are smaller than presidential elections and are often all about getting out base voters, and the GOP base hates Obamacare.
7). Will shutdown hurt Republicans in November?
GOP poll numbers plunged following the 16-day federal shutdown with surveys indicating more Americans blamed Republicans.
Although the GOP regained political ground following the rocky rollout of Obamacare, many members learned a lesson from the shutdown, contributing to a bipartisan budget deal just before Christmas to prevent another one.
But another fiscal fight looms early in 2014 over the debt ceiling and congressional Republicans have already signaled they're ready to fight.
8). How will the economy impact midterms?
"The economy is stronger than it's been in a very long time," Obama touted at a year-end news conference.
By many metrics, he's right. The stock market's soaring, unemployment's at a five year low, auto sales are at a seven-year high, and the housing sector, which dragged the country into recession five years ago, is rebounding.
But many people just don't feel that good about things.
Nearly 70% of people questioned in a CNN/ORC International poll in late December said the economy is generally in poor shape, and only 32% rated it good.
And just over half expected the economy to remain in poor shape a year from now.
The economy remains the top issue on the minds of voters, and both economic realities, and perceptions, will influence voters in 2014.
9). Will Democrats make income inequality a big issue?
Long-term unemployment benefits for 1.3 million Americans expired Saturday. Reinstating those benefits is expected to be one of the first priorities for congressional Democrats in the new year.
The President talked about extending them in his last State of the Union address, highlighted the issue in a speech in early December and make a push for it again in January.
But regardless of what happens in with extending the benefits, Democrats think they have a winning issue that can deflect from the damage done by the health care rollout. Expect a push by the White House, congressional Democrats, labor groups and progressive organizations to raise the federal minimum wage and proposals to boost the level in some crucial states in 2014.
10). Will special election serve as a barometer?
Take a vacant congressional seat in a swing district in a purple state and you get what many see as a bellwether special election that could serve as a barometer for what may happen in November.
The spotlight will shine on the March race to fill the term of Rep. Bill Young of Florida, who was in his 22nd term when he died in October.
This district is up for grabs: While Young grabbed 58% of the vote in his re-election last year, the President won the district in his re-election victory, carrying 50% of the vote. Obama also won the district in the 2008 election, grabbing 51% of the vote.
"It almost goes without saying, but this is the type of seat and race Democrats have to win in order to have any chance of gaining the 17 seats they need in 2014 to get back to the majority," wrote Nathan Gonzales, deputy editor of the Rothenberg Political Report.
11). Will Hillary Clinton announce a bid?
It's the biggest 2016 question in campaign politics: Will Hillary Clinton launch a second bid for President?
The former Secretary of State says she'll decide in 2014 about whether she'll make another run for the White House in 2016.
"Obviously, I will look carefully at what I think I can do and make that decision sometime next year," Clinton said in a recent interview with ABC's Barbara Walters.
Since Clinton stepped down as America's top diplomat in early 2013, speculation has mounted that she'll run again for the Democratic nomination. Then-Sen. Clinton battled then-Sen. Barack Obama in a marathon fight for the nomination in the first half of 2008 before she bowed out in June.
If she decides to run, Clinton would instantly become the overwhelming frontrunner for the nomination. She's been miles ahead of other potential Democratic White House hopefuls in every public opinion poll.
12). How will midterms impact potential 2016 contenders?
Does it seem like the 2016 president campaign is already underway?
With a bunch of possible White House contenders from both parties making numerous trips to the crucial early voting states of Iowa, New Hampshire and South Carolina in 2013, the answer is yes.
And expect that trend to accelerate.
One of the potential candidates, GOP Gov. Chris Christie of New Jersey is now head of the Republican Governors Association, and with three-dozen states electing governors in 2014, Christie will be crisscrossing the country, supporting some of the party's brightest stars.
But he'll also be introducing himself to those who know only the larger-than-life figure on TV.
The states that kick off the presidential primary and caucus calendar are among those holding elections next year. That itinerary works out well for someone who's got an eye on the White House.
"The chairmanship of the RGA allows a governor to run for President before he actually runs for President, building relationships with organizers in key states and expanding his network of national contributors," said Alex Castellanos, a Republican strategist and veteran of numerous GOP campaigns. "It can also warehouse staff that can later move over to a presidential campaign. He can also use the RGA to collect chits by helping fellow GOP governors whom he hopes will eventually help him."
Some other questions that may be answered in 2014: Will Sen. Marco Rubio of Florida rebound from the political damage done due to his leadership role in the Senate passage of a bipartisan immigration reform bill? Does Sen. Ted Cruz of Texas continue to be a conservative star? Will Sen. Rand Paul of Kentucky continue to play to both the grassroots and the establishment? Will Vice President Joe Biden start up a leadership PAC? And will GOP Govs. Scott Walker and John Kasich survive re-election bids?