The fight over Brett Kavanaugh's nomination to the Supreme Court is a reminder of how control of the Senate is more important than control of the House of Representatives.
Democrats will pick up Nevada's Senate seat from Republican Dean Heller, virtually all analysts believe, but they need to gain an additional seat to reestablish control. That means that all eyes will be on two Republican-held seatsâ€”in Arizona and Tennessee where the GOP incumbents are retiring and the Democrats look positioned to make a strong challenge.
Polls show Democrats leading both races, but a deeper analysis suggests that those leads might not hold up. In both cases, the Democrats start the race much better known than their putative Republican opponents in Republican-leaning, vote-rich areas. As the Republican candidates air ads in these markets, it stands to reason that their standing will improve, making each race much closer.
The Phoenix metropolitan area is Arizona's region to watch. Nearly 60 percent of the state's votes are cast in Phoenix's Maricopa County, so a candidate with a base there would clearly start with greater name recognition. The likely Democratic nominee, Congresswoman Kyrsten Sinema, has that base, having represented a Phoenix-area district since 2012. In contrast, the Republican nominee thought to have the best chance to hold the seat for the party, Congresswoman Martha McSally, has represented the Tucson area only since 2015.
This means that in prior campaigns, Sinema has aired ads reaching the entire Phoenix media market, while McSally has made herself known only to the much smaller Tucson region.
It should come as no surprise, then, that Sinema holds a large advantage over McSally in Maricopa County, a margin that represents virtually all of her current lead. In the Emerson College poll, for example, Sinema leads McSally by an eight-point margin statewide but more than 18 points in Maricopa County. Sinema leads in every one of the county's five congressional districts, including the two safe Republican seats that no Democrat ever carries. This is exactly what one would expect to find in a case like this.
But it's also clear that Sinema's lead in Maricopa County will shrink dramatically as the race heats up. Maricopa traditionally votes strongly Republican. No Democrat has carried it in a competitive race for governor, senator, or president in this century. Democrat Janet Napolitano lost it in 2002 when she defeated her Republican competitor, Matt Salmon, statewide. Even Donald Trump carried Maricopa County en route to a relatively narrow statewide victory for a Republican. All past evidence suggests that Sinema will do well just to run even in Maricopa; if she were running even there now, the Emerson poll would be virtually tied.
To a lesser extent, the same dynamic is at play in Tennessee. Former governor Phil Bredesen is the Democratic nominee, while the Republican is eight-term congresswoman Marsha Blackburn. Bredesen has run and won twice statewide while Blackburn has previously run only for Congress. Her seat has at times included portions of the two largest media markets in the state, Nashville and Memphis, but she has never before had to run in Eastern Tennessee's Knoxville or Chattanooga markets.
This region of the state has been a Republican bastion since the Civil War: even Bredesen didn't win it in his first race for governor in 2002. Yet, the Emerson poll shows him leading Blackburn by 14 percent in the three congressional districts wholly within Eastern Tennessee, even as he leads her by only six points statewide. Bredesen will do well to lose this region by only a few points on Election Day. If the Emerson poll today reflected this likely end-of-race reality, Blackburn's deficit would be within the margin of error.
These observations do not mean that Democrats will lose both races. Sinema and Bredesen are strong candidates running in what appears to be a poor year for Republicans. McSally could still lose her primary to a more Trumpian candidate like former Maricopa Sheriff Joe Arpaio, while Blackburn could find that her strong conservatism doesn't fly well with more moderate independents. But current polls do not reflect the fact that both GOP candidates will certainly do much better in these vote-rich Republican-leaning areas than they are doing right now.
That's what happened in the 2016 Indiana Senate race. Former governor and Senator Evan Bayh entered the race in the summer and quickly took a strong lead over the Republican nominee, Congressman Todd Young. Young had represented a southern Indiana seat for only six years, while Bayh had previously run and won statewide four times. Though Young had just finished a winning campaign to capture the Republican nomination while Bayh had not held office since 2010, Bayh still had significantly better name recognition at the outset. But his large lead shrunk as Election Day approached and Young's advertising made him better known. By the end of October, polls showed the race tied or with Young slightly ahead. On Election Day, Young defeated Bayh by more than 9 percent.
Democrats cannot retake Senate control without winning at least one of these seats, in addition to Nevada. Savvy observers will be watching the polls once television advertising begins in earnest in September. Barring an unforeseen event, that means that we should expect these races to follow the Indiana pattern and tighten considerably. Both seats might look like Democratic pickups right now, but by Halloween, these treats might turn out to have merely tricked unsophisticated pundits.
• 06/04/18: Republicans' Millennial Problem Isn't What You Think
• 02/26/18: Trump, Twitter, and the GOP's Improving Poll Numbers
• 07/05/17: How Reagan would fix Obamacare
• 02/08/17: The last, best hope to re-Reaganize the GOP