rochester, n.h. <u+2014> maggie hassan, the democratic governor of new hampshire now running for the senate, squeezed by an older woman grimly examining some potatoes at a grocery store here last week. <u+201c>i hope you<u+2019>ll consider me,<u+201d> ms. hassan said. the woman, still glowering, grumbled, <u+201c>i might.<u+201d> in half a dozen states, similar sentiments prevail. democrats, who just two weeks ago expressed confidence they would retake control of the senate, are now far less certain, and their fates may well be tied to the rancorous presidential race and the downbeat attitude of voters that contest has created. many thought hillary clinton <u+2019>s once-clear lead in new hampshire would all but ensure a victory for ms. hassan over the senate republican incumbent, kelly ayotte , who won her seat in a 2010 tea party -infused election. but this eastern cornerstone for democrats appears to be cracking; mrs. clinton plans to make a hastily scheduled dash to manchester on sunday. ms. hassan and ms. ayotte, both well known to voters here, are on a desperate hunt for every last vote in the state<u+2019>s grocery stores, taverns, rotary clubs, burger king drive-throughs and even town dumps, in one of the nation<u+2019>s tightest and most expensive senate races. democrats<u+2019> hopes had risen largely because of donald j. trump <u+2019>s weakness in some states and an overall disorganized republican effort to rally potential voters. now, at least four races <u+2014> in new hampshire, north carolina, indiana and missouri <u+2014> are considered dead heats, and democratic prospects are only slightly better in pennsylvania, wisconsin and nevada. an even split or a bare minimum majority for either party in the next congress, one with an aggressive policy agenda, no matter who sits in the white house, seems increasingly possible. <u+201c>i think democrats have enough opportunities to get to 50,<u+201d> said nathan l. gonzales, the editor of the rothenberg & gonzales political report , a nonpartisan newsletter, <u+201c>but i am still not clear what combination of states make that happen.<u+201d> democrats will need four more seats if mrs. clinton is elected, or five if mr. trump prevails, to regain control of the senate. in the house, republicans are bracing for a loss of possibly a dozen seats, but will almost certainly remain in control, albeit with a majority in which a conservative faction could continue to roil the party. <u+201c>this election is most like 1980,<u+201d> peter d. hart, a veteran democratic pollster, said of the election in which ronald reagan<u+2019>s large victory also delivered the senate to republicans. <u+201c>if the presidential election narrows to less than 3 percent, then democrats will need some good fortune to win control of the senate. my advice is to watch the margin between clinton and trump.<u+201d> unlike many other races around the country, the fight for the senate seat in new hampshire features two women whom voters know well in a state where most elected officials seem familiar with at least half the people they run into. ms. ayotte was the state<u+2019>s attorney general before she was elected to the senate, and ms. hassan is a product of the democratic mentoring system under senator jeanne shaheen, another former governor. both have run well-calibrated campaigns focused on the state<u+2019>s opioid problem and fiscal future. both have been accessible to voters, who expect it here, with six debates, 10 candidate forums and dozens of campaign stops. ms. ayotte runs a five-kilometer race almost every saturday in towns around the state, and favors truck stops and town dumps to meet voters. she will campaign for 24 straight hours beginning monday morning. <u+201c>it<u+2019>s going to be fun,<u+201d> she said, perhaps redefining notions of enjoyment. ms. hassan has relied on the star power of her party, campaigning in recent weeks with senator bernie sanders of vermont, who won the state big in the democratic primary; as well as senator elizabeth warren of massachusetts; michelle obama, the first lady; and vice president joseph r. biden jr. <u+201c>i am just working hard every day,<u+201d> ms. hassan said at a bakery last week. ms. ayotte has struggled mightily with the candidacy of mr. trump, at first giving him lukewarm support. and when asked during a debate if she saw mr. trump as a role model for youths , she replied, <u+201c>absolutely.<u+201d> she then put out a statement contradicting the remark, which became a bludgeon for ms. hassan. ms. ayotte finally dumped mr. trump, a dizzying ride that may have tainted her brand of independence. ms. hassan has had her own troubles with mrs. clinton. the new hampshire race has been staggeringly expensive, with over $100 million spent on behalf of the two candidates, the majority of which has supported an all-out assault of television advertising. <u+201c>i should be embarrassed to have either of you as my senator,<u+201d> larry gray, a doctor in portsmouth, groused during a rotary club meeting where ms. hassan spoke. only the senate race in pennsylvania, which has nearly 10 times the population of new hampshire, has attracted more outside money. outside spending on senate races nationally has passed half a billion dollars this cycle, a record. as in other states, there are messy battles outside the senate contest. representative frank c. guinta, republican of new hampshire, is embroiled in a campaign finance scandal that caused ms. ayotte to call for his resignation. his opponent, for the fourth time , is former representative carol shea-porter. <u+201c>the republicans are not helping themselves down ballot,<u+201d> said andrew e. smith, a political scientist and pollster at the university of new hampshire. <u+201c>when you have a party that is not unified, it makes it difficult for them to win, especially when they are not the majority party.<u+201d> ms. hassan hopes to be aided by an elaborate turnout operation conducted by the clinton campaign. but ms. ayotte is unlikely to get any corollary benefit from mr. trump, who republicans complain has a limited get-out-the-vote operation. <u+201c>i have no confidence in the trump ground game,<u+201d> said fergus cullen, a former chairman of the new hampshire republican party , noting the swarms of volunteers for groups like planned parenthood and other clinton supporters he has seen in the state, and the bumbling efforts of trump volunteers, a complaint that has been echoed in many other states. <u+201c>the idea that there is this team of republicans working together is just not true.<u+201d> still, ms. ayotte is clearly competitive in a race where both sides believe they have a slight advantage, with scant real-time proof either way. <u+201c>both candidates are both under 50 percent,<u+201d> said rich killion, a republican strategist here. <u+201c>but the weight of the stuff that has been thrown on ayotte has not had the marginal effect democrats want to open up the gap.<u+201d> the story is largely the same in north carolina, where the republican incumbent, senator richard m. burr, started late; and in indiana and missouri, where the democratic challenger, former senator evan bayh , and the republican incumbent, roy blunt, have taken a beating for their lobbying ties . in nevada, where democrats are desperate to hold onto the seat of the retiring harry reid, mr. trump has been seen as a drag on the efforts of representative joe heck to defeat the democrat, catherine cortez masto. there are also clear signs of a tightening race in wisconsin, where the republican incumbent, ron johnson, has been aided by an enormous cash infusion from outside groups in his race against former senator russ feingold, who held a double-digit lead for much of the year. in pennsylvania, senator patrick j. toomey may also be vulnerable to a negative trump effect in the race against katie mcginty. few know where the election is heading, even as so many are deeply invested in the outcome. <u+201c>i have two bumper stickers on my car,<u+201d> mr. cullen said, one for ayotte and one for gov. john kasich of ohio, a former republican candidate for president, <u+201c>which is another way of saying, <u+2018>don<u+2019>t blame me.<u+2019><u+201d> mr. cullen added, <u+201c>i feel like i have never had an election in which i have had less confidence to say how it<u+2019>s going to turn out.<u+201d> rachel shorey contributed reporting from washington. a version of this article appears in print on november 6, 2016, on page a1 of the new york edition with the headline: tossups leave senate control up for grabs. order reprints | today's paper | subscribe
tense senate tussle in new hampshire illustrates murky finish line
jennifer steinhauer