by Matthew Rusling

WASHINGTON, June 14 (Xinhua) -- This week's U.S. Republican primaries underscored the loyalty of U.S. President Donald Trump's supporters, despite over a year of controversy since he clinched the White House.

Experts said this is a good sign for the Republican Party (GOP) in the upcoming midterm elections, although it won't ensure their victory, as Democrats are highly motivated by their animosity toward the president.

"When the base of the Republican Party and the White House are walking in lock step, that's a great sign, heading into the 2018 midterms, where the GOP faces stiff headwinds in terms of trying to hold the House," Republican Strategist Ford O'Connell told Xinhua, speaking of the GOP-controlled House of Representatives.

While Trump over the past year has faced opposition from a number of establishment lawmakers in his own party, the GOP base has stuck with the president, who was a big winner in Tuesday's primary races.

Indeed, Trump has the second highest "own party" approval rating since WWII, at this stage of his term, second only to former President George W. Bush, according to a Gallup poll released earlier this month. Bush saw popularity from his own party surge through the roof after showing strong leadership in the aftermath of the Sept. 11, 2001 attacks on New York and Washington that killed nearly 3,000 people.

That matters a great deal for Trump, "because in mid-term elections, 40 million fewer voters vote. And therefore, it becomes who can better turn out their base," O'Connell said.

"As long as the Republican base sees Trump as a tireless fighter who delivers, the Republicans have a chance to hold the House and make gains in the Senate," O'Connell said.

Experts say that Trump now rules the GOP, and Republican lawmakers who stand against him will feel his wrath. That was evident earlier this week when GOP voters booted out incumbent Congressman Mark Sanford in Tuesday's primary elections.

Sanford has been highly outspoken against Trump, but lost in his efforts at re-election in his district in the state of South Carolina, after Trump blasted him on social media. As a result, political newcomer Katie Arrington, who lambasted Sanford for his lack of loyalty to Trump, clinched the election in a contest that grabbed national headlines.

Other experts, however, said fierce loyalty among Trump's base may not keep the GOP in power, as Democrats are equally united in unseating the president, who has faced mounting criticism from the Democrats.

"Having a strong base will not protect the GOP majorities because Democrats are equally united in wanting to defeat Trump," Brookings Institution Senior Fellow Darrell West told Xinhua.

"Trump owns the Republican party and it is virtually impossible for Republicans to criticize him without incurring the wrath of his base," West said.

"That means Party members will support him in anything he does, no matter how crazy, because opposition could be politically fatal," West said.