Republicans have just taken the majority of seats in the Senate. But before they even get to officially take over the Senate early next year, they're already fighting with each other over what to do in the next month.

The fight's ostensibly over whether to pass a spending bill in December that funds the government through October of next year, or only for a few months. But it's really over Obama's upcoming executive actions on immigration — or rather, what Republicans will do in response to those executive actions.

Senate Republican leader Mitch McConnell wants to pass a longer-term bill now, so that the Senate doesn't have to deal with another government-funding battle until next fall. But a group of Senate conservatives, led by Sen. Ted Cruz (R-TX), don't want to fund the government for any longer than they have to right now, so they can use funding as a weapon against any executive relief program early next year.

Here's what you need to know.

What Mitch McConnell wants: A smoothly running government

On November 5, during his first press conference after his party took the Senate, McConnell made a promise on behalf of the new GOP Congress: "Let me make it clear, there will be no government shutdowns and no default on the national debt."

In order for him to keep that promise, the GOP is going to need to stop risking government shutdown by playing chicken with bills to continue funding the government. That's going to be a lot easier if this upcoming funding deal lasts through next October, as opposed to just a few months. A short-term funding deal means that Congress would have to go through the whole funding rigamarole again early next year — with another chance for the government to shut down if it fails. And McConnell very much wants to avoid that:

McConnell has signaled to GOP colleagues that he wants to start his reign as majority leader in 2015 with a clean slate. He wants to avoid a messy fight over spending levels at the beginning of next year, which could derail one of his top priorities, passing a budget.

This isn't to say that McConnell is cool with Obama's plans to implement executive immigration action. To the contrary, he's warned Obama that it would be like "waving a red flag in front of a bull" — though it's not clear whether McConnell meant it would enrage all Republicans, or whether he meant that McConnell wouldn't be able to control Cruz and company. But he would rather pass a longer-term bill now, see what Obama does on executive action afterwards, and try to stop it in 2015 without interfering with the typical budgetary process.

What Ted Cruz wants: A commitment to fighting "amnesty"

It's generally assumed, by both Democrats and Republicans, that Obama is going to act on immigration before the end of the year — but that he's going to wait until after December 11th. The White House wants to stay out of Congress' way while it passes a funding fix, and then make its move on immigration.

This is frustrating to Senate conservatives who want to stop executive action that would protect unauthorized immigrants from deportation.

There are at least six senators who are in this camp: in addition to Sen. Cruz, there's Sen. Mike Crapo (R-ID); Sen. Mike Lee (R-UT); Sen. Pat Roberts (R-KS); Sen. Jeff Sessions (R-AL); and Sen. David Vitter (R-LA). They've declared that their highest priority is to prevent Obama from implementing any executive relief program — and that they're determined to use "all procedural means necessary" to try to make that happen.

Their plan is to make sure any funding bill explicitly says the money can't be used to implement any executive relief programs. But they can't start writing funding bans until they know what they're banning — which means they have to wait until after the administration announces its move. So naturally, they want the opportunity to write a new funding bill as soon after January 1st as possible, rather than having to wait until October.

Fundamentally, though, what Senate conservatives are fighting for here is the ability to continue to use all the tools at their disposal to keep any future Obama immigration plan from going into effect. Both Cruz and Republican National Committee chairman Reince Preibus have promised that Republicans will do anything they can to block "executive amnesty." But Sen. McConnell, along with House leaders like Rep. Kevin McCarthy (R-CA), have promised that nothing is going to stop the government from functioning smoothly. It's going to be very difficult to keep both of those promises.

CORRECTION: This article originally misidentified Senator David Vitter (R-LA). The error has been corrected.