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"He did far too much for the committee at his own expense," said one close GOP ally of Portman's. "We're going to have a very competitive race in Ohio next year."
Portman's campaign is a revealing bellwether in the battle for the Senate. If he can't hang on to a seat that once looked awfully secure, Democrats will have a good chance to reclaim the majority. And if the attributes that make Portman an effective senator aren't political assets, other senators in battleground states can't take anything for granted.
A Portman loss, combined with GOP defeats in more-liberal Illinois and Wisconsin, would mean Democrats would only be one seat away from a 50-50 Senate split—with opportunities in Florida, New Hampshire, and Pennsylvania still on the board. But if Portman prevails, Democrats would probably need a clean sweep everywhere else to retake control.
Portman certainly isn't taking his reelection for granted. He stockpiled more than $8 million in preparation for the campaign, making him the best-financed Republican senator facing a competitive reelection in 2016. His advisers argue that Ohio's sheer size makes it difficult for any politician to have universal name identification, and that early ad buys will quickly improve his standing in the state. They point to his still-solid overall favorability numbers of 43-21 in the Quinnipiac survey. They're confident that Strickland's economic record as governor gives them plenty of fodder for attack ads.
That's the optimistic view.
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But the more hardheaded view of Portman's prospects is that he's vulnerable to forces outside of his campaign's control. At a time when anti-Washington sentiment is near historic highs, his political experience and pragmatism aren't the selling points they once were. Meanwhile, the country's growing polarization means that voters are increasingly casting straight party-line ballots instead of closely assessing the merits of individual candidates. Control of the Senate is dangerously dependent on the national environment, regardless of how well the GOP's candidates run.
If those trends continue, Republicans could find their majority at risk. All politics is no longer local; each election more closely resembles a national referendum. If Hillary Clinton wins the presidency, she's well-positioned to bring the Senate along with her.
For this cycle, the map is difficult for Republicans, who are defending many more seats than their Democratic counterparts. Of the nine most-competitive Senate seats, seven are held by Republicans—and six feature sitting Republican senators. Eight of the races are being held in states that President Obama carried twice.
Democrats already are confident that they'll pick up two GOP-held seats in friendly territory. Even though Sen. Mark Kirk has a long track record of winning bipartisan support, national Democratic polling shows that he's already running well behind Rep. Tammy Duckworth. In a race where he has little margin for error, Kirk has gotten in trouble with gaffes that have drawn fire from Democrats and ridicule in the Chicago press.