Five things that would change in a Republican-led Senate

The midterm-election horserace is into its final furlong — and that means most of the attention of the political world is focused, understandably, on who’s up and who’s down; who will win and who will lose.

But if Republicans succeed in their quest to secure a Senate majority on Tuesday, what will really change on Capitol Hill?

The answer is “plenty” – both in terms of policy and politics.

Here are five areas to watch.

1. Will President Obama’s big achievements be hollowed out?

Republicans say that if they gain control of Congress they will start chipping away at two of the Obama administration’s biggest victories: financial reform and healthcare. 

The GOP could well decide against attempting another full repeal of the Affordable Care Act. But its members would probably try to eliminate the much-discussed medical device tax. They might also look at nixing the employer mandate.

The Dodd-Frank financial law is high on the hitlist of GOP lawmakers. They want to ease capital requirements for large insurance companies, create both a board of directors and a new inspector-general position for the Consumer Financial Protection Bureau, and streamline a process for banks deemed too big to fail. 

More generally, Republicans have made it clear that Obama’s regulatory agenda is a prime target.

With control over the budget and appropriations process, Republicans could cut off funding that is needed to implement or enforce regulations — including the EPA’s carbon-pollution standards for power plants, which form a big piece of the president's climate agenda. 

The GOP will also probably ramp up efforts to push through the Keystone XL pipeline and expand natural-gas exports.

2. Senate confirmations: The battlefield tilts

A GOP-controlled Senate will make it even tougher for Obama to confirm nominees, a process that hasn’t exactly been plain sailing even with Democrats in charge. 

Although Supreme Court Justice Ruth Bader Ginsburg has said she is staying put, it remains plausible that Obama could be faced with a third chance to put his stamp on the court. Republicans would find it much easier to block his choice if they held the majority in the Senate.

Obama will also nominate a replacement for retiring Attorney General Eric HolderEric Himpton HolderOvernight Defense: Trump marks 9/11 anniversary | Mattis says Assad 'has been warned' on chemical weapons | US identifies first remains of returned Korean war troops Eric Holder blasts Trump for Twitter attack on 9/11 GOP's reaction to Trump ripping DOJ indictments: Silence
 MORE, and the confirmation process will likely be fraught whomever he chooses.

Obama also isn’t like to face any shortage of executive branch, ambassador and federal judicial nominations in his final two years in office. They will all need Senate confirmation.

3. Obama to stock up on veto pens

Obama has had to pick up his veto pen on just two occasions since he took office in 2009, largely because Democrats have controlled at least one chamber of Congress throughout that time.

He will need to check he has a plentiful supply of ink if Republicans take the Senate majority. He can expect to spend his final two years using his veto to protect earlier legislative victories, rather than seriously attempting to rack up new ones.

There is some chance of bipartisan progress on issue such as immigration reform and global trade deals. But it also seems likely that Obama will need to rely on executive action if he wants to pursue many of his priorities.

4. More Benghazi, more anti-ISIS action

If Republicans take over the Senate, Sen. John McCainJohn Sidney McCainOvernight Defense: Details on defense spending bill | NATO chief dismisses talk of renaming HQ for McCain | North Korea warns US over cyber allegations Former McCain campaign manager joins Showtime's 'The Circus' NATO head shoots down idea of naming new headquarters after McCain MORE (R-Ariz.) will take the gavel at the Armed Services Committee. He is almost certain to turn the spotlight back onto the Obama administration’s missteps in Benghazi — especially the ones that Republicans say were committed by Hillary ClintonHillary Diane Rodham ClintonMueller threat to Trump grows with Manafort deal Ex-Clinton spokeswoman: Trump’s Puerto Rico claim 'grotesque' Hillicon Valley: Manafort to cooperate with Mueller probe | North Korea blasts US over cyber complaint | Lawmakers grill Google over China censorship | Bezos to reveal HQ2 location by year's end MORE, who was secretary of State at the time. 

Congressional Republican make little secret of the fact that they believe the controversy could hurt Clinton’s chances of winning the White House in 2016. Senate control would ensure they could keep it high up on the news agenda.

Republicans also are likely to push for a more aggressive U.S. response to the militants of the Islamic State in Iraq and Syria, or ISIS. They have long argued that the Obama administration isn’t being aggressive enough in that fight.

While their push probably won’t come in the form of asking for more U.S. troops in Iraq and Syria, Republicans insist that the United States ought to do more to quell terrorist threats in the region.

Republicans are faced also with a slew of expiring bills but none more important to national security than an NSA surveillance reauthorization.

It will be up to the GOP to push a bill across the finish line, just as 2016 presidential contenders ramp up their campaigns. Many national security experts have argued that letting the current law expire would be disastrous. 

5. 2016: The future starts now

Whoever wins and loses on Tuesday night, much of the political world will turn its focus to 2016 as soon as dawn breaks on Wednesday.

If the GOP controls both chambers in the new Congress, its leaders will take every step over the following two years with an acute appreciation of how their moves might affect the 2016 race for the White House. 

They will have to walk a fine line: They will want to make Democrats take tough votes while also helping those within their own ranks who might seek the Oval Office. GOP Sens. Rand PaulRandal (Rand) Howard PaulThe Hill's 12:30 Report — Trump says Dems inflated Puerto Rico death toll | House cancels Friday votes | Florence starts to hit coast The Hill's Morning Report — Sponsored by Better Medicare Alliance — Facing major hurricane, Trump is tested Rand Paul ramps up his alliance with Trump MORE (Ky.), Ted CruzRafael (Ted) Edward CruzCruz, O'Rourke agree to hold three debates in Senate race Texas city passes resolution declaring Beto O'Rourke's defense of NFL player protests 'false' Cruz-O’Rourke increasingly looks like Allen-Webb MORE (Texas), Marco RubioMarco Antonio RubioNYT says it was unfair on Haley curtain story Rubio defends Haley over curtains story: Example of media pushing bias House lawmakers urge top intel official to probe national security threat of doctored videos MORE (Fla.) and Rob PortmanRobert (Rob) Jones PortmanWealthiest Republican supporter in Ohio quits party Outdated global postal system hurts US manufacturers This week: Senate set to pass sweeping opioid package MORE (Ohio) have all had their names bandied about as 2016 hopefuls.

There will also be the concerns of those senators seeking reelection in 2016 to consider. Some centrist Republicans may seek to forge new relationships with Democrats in order to advance legislation they deem important to their reelection hopes. 

Julian Hattem, Kristina Wong, Laura Barron-Lopez, Bernie Becker, Ben Goad and Mike Lillis contributed.