Republicans need six seats to win control of the Senate. It’s no lock – but there are many paths to get there.

Here’s how it could look:

Lock down the easy three

Win the three races that most analysts anticipate they will win: Montana, West Virginia and South Dakota. The GOP is half-way there.

Go for anti-Obama territory – and don’t give ground

Republicans can go after Democratic senators in four states President Obama lost in the last election: Alaska, Arkansas, Louisiana, and North Carolina.

If they win just three of those, AND don’t lose any Republican-held seats, they have the Senate majority. That means holding onto Republican seats in Kansas, Kentucky and Georgia.

If necessary, go for Obama territory

Retaining all three of the Republican-held seats might be difficult. Independent Greg Orman has surged against longtime Republican Sen. Pat Roberts in Kansas. And Democrat Michelle Nunn has stayed competitive against David Perdue in Georgia, to say nothing of the marquee race between Senate Republican Leader Mitch McConnell and Alison Lundergan Grimes in Kentucky.

If Republicans lose any of those, it makes winning seats in states Obama won in 2012 all the more important (or winning all four of the states he lost).

The two best shots in Obama-friendly states would appear to be Colorado and Iowa, where Republican Joni Ernst has run a strong campaign against Rep. Bruce Braley.

If the races really start to turn in the Democrats’ favor, though, Republicans have other options.

New Hampshire, where Republican Scott Brown has run an insurgent bid against Democratic Sen. Jeanne Shaheen, is considered winnable for the GOP – a shift from over the summer.

And then there are the longshots – states like Virginia and Michigan that heavily favor the Democratic candidate. But as former House GOP leader Eric Cantor’s loss earlier this year to a relatively unknown Republican primary challenger showed, anything can happen on Election Day.

The Associated Press contributed to this report.