Republicans face credible challenges in 62 congressional districts in November while Democrats face competition in four.

Washington, DC – Republican Congressman Mike Bost’s big political moment this election year came in July when he and President Donald Trump toured the Granite City Steel Works near St Louis in the US heartland.

The president, appearing at a rally with Bost and other Illinois congressional Republicans, touted his steel tariffs and promised to bring industrial jobs back to the Midwest.

People in Illinois’ 12th district voted 55-40 percent for Trump over Hillary Clinton in the 2016 presidential election. Yet Bost, who has embraced Trump, is in a tight race for re-election this year.

“This is a competitive race that leans maybe slightly Republican is the way I would rate it,” said John Jackson, a political science professor at the Paul Simon Institute of Public Policy at the University of Southern Illinois in Carbondale.

In a telling sign, the Granite City steelworkers union threw their support to Bost’s Democrat challenger, Brendan Kelly, a former state prosecutor and political moderate.

On November 6, some 80 million voters – perhaps more depending on turnout – will cast ballots for all 435 seats in the House of Representatives where Republicans currently hold a 23-seat majority.

Historically called “midterm” elections, the vote is essentially a referendum on the party of the president, whose performance in office is watched closely.

“Trump’s job approval is one of the critical factors and thus there is some reason to believe a Democratic wave is coming,” Jackson told Al Jazeera.

Recent polls show US voters increasingly hold negative views of the president. Sixty percent of registered voters in a joint August 29 poll by The Washington Post and ABC News disapproved of the job the president is doing, up from 54 percent in April.

Democrat revival?

Now, as Republicans begin their re-election campaigns in earnest, most analysts are predicting that the Democrats will gain control of the House, an outcome that would match historical norms.

“My forecast is that the Democrats will pick up a net of about 30 House seats. I don’t see a huge wave. But I think they will take the House,” said Greg Valliere, chief global strategist and Washington analyst at Horizon Investments LLC, a financial advisory firm.

Republican losses, however, easily could be higher depending on the depth of a potential backlash against Trump.

Republicans face credible challenges from Democrats in 62 congressional districts while Democrats face competition in only four, according to The Cook Political Report, a non-partisan publisher of US political analysis.

In the state of California, affluent suburban voters in Orange County have historically provided Republicans with a reliable base of support. Not so this year.

“We used to be the county that Ronald Reagan said all good Republicans go to die [in],” Dan Chmielewski, publisher of TheLiberalOC, an Orange County political blog, told Al Jazeera.

“Hillary won Orange Country in 2016, the first time a Democrat has taken this county since Franklin Delano Roosevelt. There are significant cities that have voter registrations that are majority Democrat now,” he said.

‘House battlefield’

Three Orange County Republicans face Democratic challengers in races analysts rate as toss-ups.

In the agricultural San Joaquin and San Fernando valleys, where Hispanics make up one-third or more of voters and Trump’s anti-immigrant policies hurt migrant workers, two more Republicans face competitive races.

In particular, Representative Dana Rohrbacher, now in his 15th term as a congressman, faces criticism at home for his connections to Russians amid the US Department of Justice’s special investigation into Trump’s campaign and potential collusion with Russian interference in the 2016 presidential election.

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Rohrbacher blames a “deep state” conspiracy for the investigation of Trump and says he doubts the veracity of criminal charges brought against Russians by Special Counsel Robert Mueller.

Rohrbacher’s opponent Harley Rouda has aggressively tied him to Trump and argued the Republican congressman has failed to hold the president accountable, a campaign theme that plays well in California.

Nationwide, a combination of demographic change and disaffection with Trump’s brand of politics – particularly among suburban white, college-educated women – has created a challenge for incumbent House Republicans who four years ago might have counted on easy re-elections.

“The House battlefield is largely in districts that either Clinton won, or where Trump didn’t really run that far ahead. There are a lot of suburban districts where they like Republicans but maybe not a Republican like Trump,” Kyle Kondik, who analyzes House races for the University of Virginia Center on Politics, told Al Jazeera. “And so, I don’t think the president is an asset.”

‘Gift to the wealthy’

Democrats have led Republicans in national congressional preference polls all year. The average spread has widened recently to 8.4 percent, according to RealClearPolitics.com.

House races in Texas are emblematic both of the depth of Republican troubles this year and how American politics are shifting at the grassroots level in response to Trump.

Representative John Culberson has held the wealthy Texas 7th district in suburban Houston for 18 years. It’s a district that was held by former President George H W Bush when he began his political career. Today, it is more diverse, with a population that is 44 percent white, 32 percent Hispanic, 13 percent black, and 10 percent Asian.

Culberson now faces a tough challenge by Democrat Lizzie Fletcher, a relatively inexperienced, progressive liberal who is focusing her campaign on organising local turnout and resentment about the federal response to Hurricane Harvey, a category-4 storm that caused $125bn in damage in August and September 2017.

A senior member of the House committee that doles out federal money, Culberson played a key role in delivering billions in federal aid to Texas after Harvey but hasn’t been personally visible in the district. Like many other Republicans, his hopes of campaigning on the popularity of a huge tax cut enacted in 2017 under Trump have fallen flat.

“An awful lot of Republicans thought the tax cuts would be a major plus for them in the election,” Valliere said. “We’ve seen a lot of Republicans abandoning campaign advertising, bragging about the tax cuts. People, especially the Trump base, feel that the tax cuts were a gift to the very wealthy and the corporations.”

Unpopular policies

Other pieces of the Republican agenda in Congress have proven unpopular, particularly the 2017 repeal of “Obamacare” – the 2010 Affordable Care Act – that set up mandated health insurance markets designed to cut costs and make healthcare more accessible for Americans.

In Illinois, Bost was forced to discontinue holding town hall meetings to avoid irate constituents.

The National Republican Congressional Committee, which is the political arm of the House Republican party, adopted the theme, “Protecting Our Historic Republican Majority” in its campaign and fundraising communications. One by one, it is attempting to paint Democrats as “radical leftists” opposed to “conservative values”.

But without a popular national platform, the anti-Trump political climate has left Republicans scrambling to play on local issues or, in some cases, use tricks to weaken the appeal of Democratic opponents.

In Virginia’s 7th district, defined by suburbs of the state capital Richmond, Tea Party darling Dave Brat is in a tough fight against Democrat challenger Abigail Spanberger, a former CIA operative whose security clearance application was improperly leaked by a political group tied to Republican House Speaker Paul Ryan.

Ryan’s working-class Wisconsin district outside of Milwaukee was carried by Trump 53-42 percent over Clinton in 2016. He announced in April he would not seek re-election, one of 39 House Republicans choosing to retire rather than face voters this year.

“There’s where the Achilles heel in the Trump movement is,” Jackson said.