
 
 Democratic candidate for U.S. Senate Michelle Nunn, right, participates in a rally before casting her own ballot in early voting at the Adamsville Recreation Center in Fulton County on Oct. 15 in Atlanta. Nunn is running against Republican David Perdue. (David Tulis/AP) 
 
 The Senate race in Louisiana is headed for a runoff, and the race in Georgia is likely to join it. That means we could have two Senate races stretching into December and one of them into January — with control of the U.S. Senate very possibly in the balance. 
 
 And accordingly, we're starting to focus a little more on runoff polling. 
 
 These surveys suggest that Democrat Michelle Nunn has the runoff edge in Georgia (she led 51-47 in a CNN/ORC poll last week) and Republican Rep. Bill Cassidy has the edge in Louisiana (he's up 48-41 in a just-released USA Today/Suffolk poll). 
 
 But when it comes to these pre-Election Day polls of hypothetical runoffs, caution is the watchword. 
 
 The runoff polls, for instance, apply the same electorate from Election Day to the runoff. And especially in Georgia, where the runoff is still more than two months away and turnout will be lower, it's not a great measure. (Turnout in Georgia's last two Senate runoffs — in 1992 and 2008 — has been between 81 and 84 percent as high as turnout in the following midterm elections.) 
 
 In addition, that drop in turnout almost always comes at the expense of the Democrats. The last five statewide runoffs have seen Democrats lose an average of nine points from their Election Day margins. In other words, if Nunn's campaign were offered the same electorate Jan. 6 as Nov. 4, it would take it in a heartbeat. But that's probably not feasible — especially given that this will be the state's first post-New Year's Day runoff. 
 
 Turnout in Louisiana runoffs, by contrast, can be pretty similar to a midterm election. That's because the runoff is basically the general election in Louisiana, following the nonpartisan jungle primary on Election Day. In 2002, for instance, Sen. Mary Landrieu (D-La.) faced a runoff in which turnout was basically just as high (99 percent) as it was on Election Day. 
 
 But runoff turnout also varies significantly based on what kind of races are being held. In congressional runoffs, for instance, turnout can drop by as much as one-third if there isn't a big-ticket runoff at the top of the ballot getting voters back to the polls. 
 
 And while Landrieu has survived two runoffs, the odds in this one are stacked against her. The Suffolk poll shows Landrieu at 36 percent, Cassidy at 35 percent, tea party favorite Rob Maness (R) at 11 percent and 18 percent undecided. 
 
 Here, it's actually more instructive to look at the the Maness voters and the undecideds than the runoff poll. As Suffolk pollster David Paleologos notes, 89 percent of Maness supporters and 60 percent of undecided voters have an unfavorable opinion of Landrieu. These are the people Landrieu would need to win over in order to get to 50 percent plus one Dec. 6. 
 
 But while all of those voters appear likely to vote on Election Day, the question is who among them will turn out for the runoff. If Maness voters are disenchanted enough with Cassidy, do they stay home? And who among the undecideds comes to the polls? Landrieu is at 75 percent among the black vote, for instance, and if she can drive that number up, it would certainly help. 
 
 In both of these cases, though, the most important thing to remember is that there are still several weeks of the campaign to go, and especially in a state like Louisiana, both sides have effectively been biding their time for the runoff for a while now. The last few weeks is when stuff starts happening. 
 
 And lastly, consider the very real possibility that these races could be pivotal for control of the Senate. If that's the case, these two states will be inundated with money from all over the country, and nobody will be able to escape the importance of their state's runoff. And conversely, if the Senate majority isn't at stake, these could turn into pretty sleepy contests. 
 
 If could be a fun few weeks. ||||| WASHINGTON The fight for control of the U.S. Senate could last far past the Nov. 4 election, with possible run-offs in Louisiana and Georgia and surprising surges by independent candidates in Kansas and South Dakota creating new uncertainty for both parties. 
 
 All four states are critical to Republican efforts to pick up the six Senate seats they need to hold a majority of the 100-member chamber, and the added unpredictability could extend the battle for Senate control into December or even early January. 
 
 In Louisiana and Georgia, no Senate candidates are polling above the 50 percent level needed to avoid a run-off between the top two finishers. The Louisiana run-off would be on Dec. 6, and the Georgia run-off would be on Jan. 6, the day the new Congress is scheduled to convene. 
 
 The picture is further muddied by the rise of strong independent candidates in Kansas and South Dakota who could join the Senate without clear allegiance to Democrats or Republicans. If Senate control hinges on one or two seats, they would face immense pressure from both parties to join their ranks. 
 
 "The fact of the matter is we may not know who is going to control the Senate on November 4," said Jim Manley, a former longtime aide to Democratic Majority Leader Harry Reid. "It may take at least a month for it to all play out." 
 
 The stakes will be high for both parties. With a dozen or so tight races being waged across the country, any state could wind up producing the kingmaker who decides whether Republicans or Democrats control the Senate. 
 
 Republicans are expected to maintain their majority in the House of Representatives, so winning the Senate would give them further power to block President Barack Obama's agenda in the last two years of his term. 
 
 In the case of a 50-50 split in the Senate, Vice President Joe Biden, a Democrat, would represent the deciding vote. 
 
 Both parties are preparing for overtime battles. A run-off is expected in Louisiana, where two Republicans are trying to unseat Democratic Senator Mary Landrieu. In Georgia, a Libertarian candidate could siphon away enough votes to keep the Republican and Democratic contenders just below 50 percent. 
 
 In Kansas, Republican Senator Pat Roberts faces a tough challenge from independent Greg Orman, whose candidacy was bolstered last month when the Democrat dropped off the ballot. Recent polls in South Dakota show a tight three-way race between Republican governor Mike Rounds, Democrat Rick Weiland, and independent Larry Pressler, a former Republican senator. 
 
 If either independent wins he will face heavy pressure from both parties to side with them in the new Congress, especially if the Senate balance of power hinges on his decision. Maine independent Angus King could also come under the spotlight. He currently caucuses with Democrats but has said he will consider switching parties after the election if he thinks it is best for Maine. 
 
 The prospect of a split Senate also raises the possibility of party-switching from lawmakers who do not always align with their own parties. This would not be unprecedented: in 2001, for example, Vermont Republican Jim Jeffords became an independent, joining Democrats in votes to give them a majority. 
 
 (Reporting by Gabriel Debenedetti; Editing by John Whitesides, Frances Kerry and Andrew Hay)
– Think the Nov. 4 election will determine which party controls the US Senate? Not necessarily: Louisiana and Georgia are facing possible run-offs, while Kansas and South Dakota have strong independent candidates who could become king-makers if either party needs one more to control the 100-member legislative body, Reuters reports. No candidates are polling high enough in Louisiana and Georgia to avoid a run-off, which could extend the battle for Senate control to Dec. 6 in Louisiana and Jan. 6 in Georgia. If independents win in Kansas or South Dakota, they may eventually turn Democrat or Republican. "The fact of the matter is we may not know who is going to control the Senate on November 4," says a former aide to Harry Reid. "It may take at least a month for it to all play out." Democrat Michelle Nunn would apparently win a Georgia runoff (by 51% to 47%, per a CNN/ORC poll) while Republican Rep. Bill Cassidy might win in Louisiana (by 48% to 41%, per a USA Today/Suffolk poll), reports the Washington Post. Other runoff data abounds: In Georgia, for example, turnout usually drops from Election Day to runoff, especially for Democrats, while Election Day numbers tend to hold steady in Louisiana. In a Louisiana runoff, Sen. Mary Landrieu would need to sway independents and supporters of tea party candidate Rob Maness, who view her unfavorably by sizable majorities. What's more, a sudden influx of cash could influence either runoff if Senate control hangs in the balance. "It could be a fun few weeks," quips the Post.