(Reuters) - For months, Republican U.S. Representative Steve Chabot was running about even with Democratic opponent Aftab Pureval in his traditionally conservative southwest Ohio district.

But as the Nov. 6 elections approach, the contest has begun breaking in Chabot’s favor, one of about half a dozen races in conservative-leaning districts where improving Republican odds are stoking speculation of a tightening battle for control of the U.S. House of Representatives that could limit a Democratic “blue wave.”

Despite the gains, most independent analysts still predict that Democrats will pick up the 23 seats they need to gain control of the House, where they would be in a position to derail or stall much of Republican President Donald Trump’s policy agenda.

A Reuters analysis of election-prediction data by three major political handicappers - Cook Political Report, Inside Elections and the University of Virginia’s Center for Politics - showed that while Republican ratings had improved since early September in seven of 65 competitive races, Democrats had gained in 48 races.

But in Ohio and other districts where Republicans like Chabot have risen in recent opinion polls and in the rankings of political handicappers, their resurgence reflects Trump’s success in charging up his base, helped by his multiple political rallies and this month’s confirmation of his Supreme Court nominee, Brett Kavanaugh.

Between greeting people walking into a high school football game on a recent October evening in Mason, Ohio, Chabot told Reuters that the Senate battle over Kavanaugh, who was confirmed 50-48 despite being accused of a decades-old sexual assault, had energized conservative voters.

“Kavanaugh mattered,” the 11-term congressman said. His district, covering much of Cincinnati and its suburbs, backed Republicans, including Trump, in four of the past five presidential races. “Our base, I think, were a bit complacent there for a while. I think things have really come around.”

In mid-October, the Center for Politics reclassified Chabot’s race to “leans Republican” from a “toss up” after concluding the Democrat’s spirited challenge may have stalled.

The Republican gains coincide with renewed Republican strength in a handful of Senate races with largely rural and white populations.

By contrast, Democratic candidates have made strides in often racially diverse, urban or suburban Republican districts, including areas that backed Republican Mitt Romney for president in 2012 and then went for Democrat Hillary Clinton in 2016.

Democrats are also performing well in some districts that backed Democratic President Barack Obama in 2012 and then narrowly went for Trump.

‘TRUMP COUNTRY’

But the data suggests there is a clear opportunity for a Republican firewall in the fight to control the House: Trump Country.

Republicans in competitive districts where Trump prevailed by double-digit margins two years ago have shown the most obvious signs of bouncing back, said David Wasserman, who analyzes House races for the Cook Political Report.

“What it suggests is that cultural flashpoints like the Kavanaugh confirmation fight and migrant caravans are better suited to rallying and awakening Trump’s base than tax cuts,” Wasserman said, referring to the president’s recent focus on a group of thousands of migrants fleeing toward the United States from Honduras.

On the campaign trail, Republican candidates are touting the strong economy while warning that voting for Democrats could lead to a liberal takeover of Congress.

In response, Democrats have pounded Republicans on healthcare, wagering that the Republican-led effort to repeal Obama’s Affordable Care Act has angered working- and middle-class voters.

In the Ohio race, Pureval, a county clerk of courts of Indian-Tibetan descent, said he thought Democratic voters were motivated enough by healthcare to defeat Chabot. “The energy is on our side,” Pureval said.

GROWING CONFIDENCE

While Republicans are favored to maintain control of the Senate, they face fundamental problems keeping the House - including defending some 40 open or vacant Republican seats, the most since at least 1930.

But in conservative areas where Trump remains popular, from upstate New York to southern Illinois, several Republican incumbents said the odds were moving in their favor.

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Buoyed by the Kavanaugh debate and a robust economy, those Republicans have less concern about supporting Trump’s agenda than candidates in suburban regions, who must balance appealing to core Republican voters and distancing themselves from Trump to attract moderates.

Just weeks ago, Republican incumbent Mike Bost’s race against Democrat Brendan Kelly in Illinois’ 12th Congressional District was considered even.

Kelly, a state prosecutor and Navy veteran, has drawn comparisons to Conor Lamb, a moderate Pennsylvania Democrat who pulled off a surprising special election win in a deeply conservative district in March.

But a New York Times/Siena College poll last week gave Bost a 9-point lead, up from 1 point in September. Cook Political Report and the Center for Politics subsequently shifted their ratings of the race to “leans Republican” from “toss up.”

The district had one of the country’s biggest swings toward Trump in 2016, voting for him by 15 points after narrowly supporting Obama in 2012. Trump appeared alongside Bost at a campaign rally in the congressman’s hometown of Murphysboro on Saturday.

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Bost touts Trump’s tax cuts and steel tariffs, although he said he sometimes disagreed with the president’s style.

“The people who voted for Trump in my district are very, very happy with what Trump has done,” Bost said in an interview before a recent campaign event in Alton, Illinois.

ENTHUSIASM GAP

With dozens of House races nationally neck and neck, Democratic Party strategists and candidates said the enthusiasm gap remained on their side.

“If you’re like most people here and you’re getting screwed, falling farther and farther behind, then I think they’re going to vote for us,” Kelly said at a restaurant near his Belleville, Illinois, office.

Like many Democrats running in Trump Country, Kelly has largely avoided mentioning the president during the campaign, instead focusing on kitchen-table issues like wage stagnation.

Even in districts where Trump only narrowly won, some Republicans are trying to capitalize on an energized conservative base.

In New York’s 19th Congressional District, a sprawling, largely rural area, polls show Republican incumbent John Faso effectively tied with Democrat Antonio Delgado in one of the country’s most expensive House races. Like Bost and Chabot, Faso lags his opponent in fundraising, although millions in outside spending have helped the Republicans close the gap in each district.

The district voted for Trump in 2016 after supporting Obama in 2008 and 2012, suggesting Faso could prevail if Trump’s base turns out to vote.

Like other Democrats, Delgado has hammered Faso for stating he wants to protect patients, despite his vote to repeal the healthcare law, accusing the Republican of “unfathomable” hypocrisy.

For his part, Faso told Reuters at a recent firehouse dinner in Jeffersonville, New York, that tactics Democrats used to press sexual assault allegations against Kavanaugh “really awakened Republicans.” In a familiar Republican attack, he sought to tie Delgado to House Minority Leader Nancy Pelosi.

“I represent the kind of mainstream view on the role of government. He represents an expansive view of the role of government,” Faso said. “Most people in this district agree with me.”

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