Democrats and Republicans have placed very different tactical bets in this year’s Senate races. Republicans are betting that President Obama’s low job-approval rating (40% in Wednesday’s Gallup poll) rubs off on Democratic candidates. In midterm elections, candidates of the president’s party have historically ended up with vote totals close to his approval rating. For example, Democratic Senate candidates ran on average 3.7 points behind Mr. Obama’s job approval in 2010. GOP Senate candidates ran on average 1.3 points ahead of President George W. Bush ’s job approval in 2006.
In this year’s 11 most-competitive Senate contests, Democrats must run far ahead of the president’s job approval to escape defeat. According to the Wednesday Huffington Post’s Pollster aggregate summaries, Mr. Obama’s job approval is 35% or less in Alaska, Arkansas, South Dakota and West Virginia; 40% or less in Colorado, Iowa, Louisiana, Montana and New Hampshire; and 45% or less in North Carolina and Michigan.
Democratic Senate candidates in these states are desperately trying to detach themselves from the leader of their party. Asked during a recent debate if she had voted for Mr. Obama, Kentucky’s Alison Lundergan Grimes refused to answer, claiming a “constitutional right to privacy.” When Arkansas Sen. Mark Pryor was asked last week if he thought “the Obama administration has done an appropriate job handling the Ebola crisis,” he paused, then answered, “Um, I would say that it’s hard to know.”
Democrats are also attacking Republican candidates with a negative ad blitz. As of Tuesday, Democratic candidates and groups have spent $222.5 million for television ads from Oct. 1 through Election Day. While Republican candidates and groups have spent $264.8 million, Democratic groups reserved more of their time earlier, paying much lower rates. This translates into more Democratic ads than Republican spots.
However, several GOP candidates in key states have done very well raising money in recent months, and they (as opposed to groups) can buy ad time at the lowest rate. While not all candidates have reported their third-quarter (July-September) numbers as of this writing, Republican contenders have outraised Democrats at least in Alaska, Arkansas, Colorado, Iowa, Louisiana, Montana, New Hampshire and West Virginia. They will use those dollars to even up the number of ads. The National Republican Senatorial Committee had its best September ever with $15.5 million, almost matching the Democratic Senatorial Campaign Committee’s $16 million haul.
Money and ad buys matter, but what matters more is whether the quality of the candidates’ messages will attract undecided voters in the final weeks. Here, too, both sides are making different bets.
Republicans are counting on undecided voters breaking against the party in power. Democrats are counting on undecideds to stay home or to split evenly, with as many turned off by individual Republican candidates as are down on the president. This doesn’t appear to be happening.
In the Real Clear Politics average of polls, Republican challengers lead in eight of the 11 most-contested races, with nine improving their numbers or margins since Sept. 1. Republicans also lead and have improved their numbers or margins in all three vulnerable GOP seats: Kansas, Kentucky and Georgia.
Democrats ran an impressive get-out-the-vote effort in 2012 and say their ground game will produce victory this year. Republicans also are spending heavily and deploying new technology and data. This matters: A study by Harvard’s Ryan Enos and the University of Chicago’s Anthony Fowler found Mr. Obama’s 2012 ground game produced a 1.6% turnout advantage. If Democrats keep that edge this year, it erases the GOP’s leads in Colorado and Iowa.
But the Democratic advantage may not be holding. Take Iowa: At this point in 2010, 18,835 more Democrats had returned early ballots than Republicans. This year the Democratic lead has been cut to 8,951. Even with their 2010 lead, Democrats lost that year’s races for governor and senator.
Finally, Democrats are betting on independent candidates, hoping supposed independent Greg Orman beats Kansas Sen. Pat Roberts, and that South Dakota’s Larry Pressler, a former Republican who supported Mr. Obama, drains enough GOP votes to defeat Republican Mike Rounds.
Republicans are hoping they can show voters that these independents are Obama supporters hiding their Democratic affiliation. That may be working in Kansas. Mr. Roberts was tied with Mr. Orman on Wednesday in the RCP average, having erased a 5.3-point Orman lead in just two weeks.
Surprises are possible in the remaining 19 days before the election. But there are a dwindling numbers of cards in the deck, and Republicans appear to have the better hand.
A version of this article appeared October 16, 2014, in the U.S. edition of The Wall Street Journal, with the headline The Republican Election Hand Gets Better and online at WSJ.com.