President Trump pauses while speaking to members of the media Wednesday on the South Lawn. (Al Drago/Bloomberg News)

President Trump’s vows to end birthright citizenship and dispatch a growing number of troops to the border have scrambled the final days of the midterm campaign for both parties — repelling moderate House Republicans in swing districts but prompting some red-state Senate Democrats to align themselves with Trump’s hard-line stances. 

Those shifting alliances reflect how much Trump — while his party would like to focus on the economy and Democrats want the spotlight on health care — has dictated the rhetorical terms of the campaign. Trump on Wednesday launched a six-day, eight-state swing that will take him to conservative states as he seeks to retain GOP control of the Senate — with immigration sure to remain front and center.

Trump’s anti-immigration rhetoric propelled him to the GOP presidential nomination and the White House in 2016, and he is counting on similarly inflammatory words and images to help the GOP hold its congressional majorities. 

The president tweeted a video Wednesday that featured Luis Bracamontes, a Mexican immigrant in the United States illegally who was sentenced to death this year after he was convicted of killing two police officers in California — using the image to make the demand: “Vote Republican now!”

Before taking off for a campaign swing to Fort Myers, Fla., Trump also floated the idea of deploying as many as 15,000 troops to the border — just days after the Pentagon said it would send about 5,200 active-duty troops there, in addition to the 2,000 National Guard members already present. He also claimed without evidence that the population of immigrants in the country illegally could be as large as 25 million or 30 million. The nonpartisan Migration Policy Institute puts the estimated size of the undocumented population at 11.3 million. 

Trump also dismissed suggestions that he was fearmongering with his increasingly aggressive immigration rhetoric, such as his frequent references to a caravan of migrants heading north, including many destitute families, that is still hundreds of miles south of the U.S.-Mexico border. 

“Oh they’ll be here fast. They’re trying to get up any way they can,” Trump told reporters shortly before leaving for the first of his 11 campaign rallies through Election Day. “We’re going to be prepared. They’re not coming into our country.”

At the rally, Trump told the crowd that “we’re getting prepared for the caravan, folks.”

“You don’t have to worry about that,” he said. Providing no evidence, Trump continued: “They’ve got a lot of rough people in that caravan. They are not angels.”

Trump’s legally questionable call to revoke birthright citizenship through a unilateral executive order has drawn opposition from House Speaker Paul D. Ryan (R-Wis.) — prompting a presidential rebuke Wednesday, delivered via Twitter — as well as rejections from House Republicans in competitive reelection contests, such as Reps. Mike Coffman (R-Colo.) and Carlos Curbelo (R-Fla.). 

But another Republican candidate in a closely contested House race, Maria Elvira Salazar, said Wednesday that the clause of the 14th Amendment that provides the constitutional underpinning for birthright citizenship “needs to be reviewed,” according to the Miami Herald

“I think the president is saying what I think my community shares, the fact that we do not want abuses,” said Salazar, who is running for election in the district that is being vacated by retiring congresswoman Ileana Ros-Lehtinen (R-Fla.) — and that Democrat Hillary Clinton won in 2016 by 19 percentage points. “The Constitution says very clearly that those that are born here are citizens, but we need to see to what extent.”

On the Democratic side, Sen. Joe Donnelly (D-Ind.), a moderate running for reelection in a conservative state, appeared to leave the door open to legislation that would end birthright citizenship, the concept that nearly anyone born on American soil is automatically a citizen of the United States. 

“We have to take a look at that legislation,” Donnelly said during a debate Tuesday evening about a bill that would revoke the right, adding, “I’d want to see that legislation and make sure it was constitutional and review it first.”

Asked about those comments Wednesday, Donnelly’s campaign released a statement from the senator saying the 14th Amendment is “clear” — and “what’s also clear is that our immigration system is broken.”

“As I have done in the past, I will work with both parties to find a solution that secures our borders and fixes our broken immigration laws,” Donnelly said.

But Donnelly is far from the lone Democratic Senate candidate in recent days to adopt immigration stances that seem almost Trumpian in nature. 

In an interview with Fox News on Monday, Sen. Claire McCaskill (D-Mo.) urged Trump to “use every tool he has at his disposal” to halt the caravan of migrants traveling north to the United States, adding, “I 100 percent back him up on that.”

Calling for a speedier process for migrants seeking asylum, McCaskill said, “I do not want our borders overrun, and I support the president’s efforts to make sure they’re not.”

And in Tennessee, Democrat Phil Bredesen released an ad Tuesday that promoted his decision as governor more than a decade ago to deploy 1,600 members of the Tennessee National Guard to the southern border. That ad was accompanied by an op-ed in the Tennessean that warned both parties against using the caravan issue to “inflame passions” over the sensitive topic.

“Actions speak louder than words,” the ad says. “In 2006, when the president said he needed help to secure the border, Tennessee Governor Phil Bredesen didn’t wait to be asked. And he didn’t play any politics.”

Immigration has become an increasingly central issue for the GOP in other closely watched Senate races. A CNN poll released Wednesday showed that immigration is now the top issue for Republican voters in Nevada and Arizona, with 42 percent of Republicans in Nevada now saying immigration is the most important issue in their Senate vote, while 50 percent in Arizona say the same. 

In Tennessee, immigration has risen to the second-most-important issue for voters there in internal Republican polling, according to one official with knowledge of the numbers. 

“I’m not surprised to see the scramble [among Democrats]. I think at this stage, it’s a little inauthentic,” said GOP strategist Josh Holmes, a former chief of staff to Senate Majority Leader Mitch McConnell (R-Ky.). Immigration “has a significant resonance within the base of the Republican Party, but it has more independent pull than one would think.”

The contrast between the parties has become sharper this year, Holmes added, particularly as leading Democratic politicians increasingly embraced liberal positions on immigration, such as abolishing the federal agency that enforces U.S. immigration laws. 

Tyler Moran, the director of the Immigration Hub, which advises a wide range of progressive organizations on immigration policy, said that the moderates taking a more conservative tack on immigration were the outliers and that congressional and gubernatorial candidates nationwide were largely “rejecting Trump’s strategy of lies and division.”

“First of all, every single one of those Democrats voted for immigration reform,” said Moran, who worked on immigration issues under then-Senate Majority Leader Harry M. Reid (D-Nev.) and in the Obama White House. “Yes, in their tough races, I wouldn’t agree with the way they’re approaching this. But we have a big-tent approach to immigration.”

Democratic officials also said that moderates in closely watched Senate races this fall have long touted their border-security bona fides — far before Trump amped up his focus on the issue as part of his closing argument in the midterms.

“Among Republicans, we’ve certainly seen that immigration more regularly tops the list of issues,” said Lauren Passalacqua, the communications director at the Democratic Senatorial Campaign Committee. “But I think what we have seen that is consistent is that among independents, obviously Democrats but even among Republicans, the Venn diagram is still health care.”