Veteran Republicans are fretting that their party is ill-prepared for a brutal midterm campaign that will be largely dictated by President Trump.

After years of running against former President Barack Obama, and with so many Republicans in Congress having been elected since the GOP wave elections of 2010 and 2014, few have experience in withstanding the sort of strong headwinds generated by full control of government and an unpopular president of their own party.

[Republicans not running for re-election in 2018]

Many Republicans appear unconvinced that major Democratic gains are even possible this November. Despite polls showing danger ahead, they are comforting themselves with the memory of Trump’s unlikely victory, in defiance of long political odds and expert prognosticators.

“There’s probably is a little bit of optimism that, we’re not going to lose the majority — that it’s going to be bad but we won’t lose,” a House Republican with deep political experience told the Washington Examiner Thursday, on condition of anonymity in order to speak candidly. “I think it’s very likely we’ll lose the majority if we don’t change some factors. We’ve got to change the landscape or we’re going to lose the majority for sure.”

Sen. John Thune of South Dakota is encouraged by the initial precautions his party is taking to protect its majorities in Congress. The third-ranking Senate Republican is optimistic that a booming economy and recently passed tax overhaul that could cut taxes for millions of voters gives the GOP a strong opportunity to hold the line.

Thune lived through the Democratic tsunamis of 2006 and 2008, each a rejection of GOP leadership in Congress and President George W. Bush. He warned fellow Republicans to be mindful of history, and the pitfalls of being tied to a polarizing president whose job approval rating has hovered around 40 percent for most of his first year in office.

“Most midterms are about the incumbent in the White House and I think this midterm will largely about that too,” Thune told reporters this week.

Midterm elections historically benefit the party out of power in the White House. Ratcheting up the threat level for the Republicans are Trump’s low approval ratings and a generic ballot — testing which political party voters would prefer control Congress — that heavily favors the Democrats.

To ensure rank-and-file Republicans treat the risks to their power seriously, and don’t dismiss the warning signs as “fake news” or Trump bias, GOP leaders are working overtime to create a sense of urgency among their members and equip them for battle.

In the House, where the 24-seat Republican majority is particularly vulnerable, the National Republican Congressional Committee, the House GOP campaign arm, is regularly counseling incumbents in battleground districts.

In the Senate, where Republicans hold a 51-49 majority, GOP leaders are warning against complacency. Most seats up for election this year are held by Democrats, many situated in states Trump won. “Don’t fall in love with the map,” Senate Majority Leader Mitch McConnell, R-Ky., has cautioned. “The map doesn’t win elections.”

Leaving nothing to chance, Republican leaders are planning a major presentation on the 2018 elections during the upcoming joint House-Senate policy retreat in West Virginia to detail and drive home the political challenges confronting the party.

The Republicans picked up 63 Democrat-held House seats and a half-dozen Senate seats on Election Day 2010. After suffering minor losses in 2012, when Obama was re-elected, the GOP rode a second wave of gains in 2014, winning 13 additional House districts and flipping nine Senate seats.

Combined with the number of Republicans elected to GOP-held seats during that same period, that makes for a lot of Republicans who have only tasted victory during their tenure in Congress. Still, Republican insiders are expressing confidence that their message is being heard and that these incumbents are doing what is necessary to survive in a turbulent atmosphere. Rep. Ryan Costello, elected in 2014, is one who hasn’t let his guard down.

The Pennsylvania Republican has the benefit of representing a swing suburban district that forces him to stay aggressive and engaged. He regularly holds town hall meetings and stays attentive to his constituents’ concerns. Costello said that his impression is that his Republican colleagues are largely cognizant, ready, and doing what’s necessary to win.

“Everybody is aware of what the environment is because they deal with … people every week protesting outside their office — I know I do,” he said. “There’s a lot more intensity right now than there ever has been.”