DES MOINES, Iowa — Republican presidential candidate Scott Walker continued his rightward shift on immigration Monday in Iowa — part of his anti-establishment pitch to conservatives as Donald Trump captures that sentiment.

Walker repeated his call for a border fence between the U.S. and Mexico on Monday similar to the one separating Israel from Palestinian territories in the West Bank, said there should be "no sanctuary cities in this country" and "I don't believe in amnesty."

"I was in Israel earlier this year, they built a 500-mile fence and they have it stacked and it's lowered terrorist attacks in that region by about 90-plus percent. We need to do the same along our border, we've obviously got a bigger border, about four times that, but we're a country that should be able to hold that," Walker said while speaking on the Des Moines Register soapbox at the Iowa State Fair.

Walker said earlier on Monday that his immigration plan is similar to Trump's. This year, Walker has tacked to the right on immigration, focusing on immigration enforcement like many Republicans, but also suggesting he'd examine the current legal immigration system, to ensure it protects American workers. Looking at legal immigration levels is a position popular with segments of both left and right, but generally a position rejected by the business wing of the Republican Party.

Speaking to reporters after his state fair speech on Monday, Walker seemed to indicate he doesn't support birthright citizenship. Walker told one reporter that he would end birthright citizenship, though he wouldn't answer when asked whether American-born children of illegal immigrants should be deported, which is a tenet of Trump's plan.

"Even Harry Reid said it's not right for a country to recognize birthright for people, for families who have not come in legally," Walker said. "But in terms of going forward I'm going to support a legal immigration system that puts a priority on the impact on American working families and their wages."

"I've talked about how going forward we should change the rules, the law, but I think in terms of deporting, the best thing we can do is enforce the law," Walker said when asked whether children born in America to immigrants who came here illegally should be deported.

"What we should do is enforce the law," Walker said when asked again. "If we enforce the law, we're not gonna have that problem going forward, a lot of people in the media here and elsewhere want to talk about several steps down the way," Walker said, saying that it was important first to secure the border and enforce immigration law.

In this summer of anti-establishment fervor, Walker seems to be re-contextualizing himself as an outsider who has bucked his party's establishment. In his speech, Walker repeatedly mentioned that not only did he beat back the unions — a pillar of his pitch to conservative voters — but that he also went against the Republican establishment. Walker, once viewed as the favorite to win Iowa, is now lagging behind as anti-establishment candidates like Trump and Ben Carson are surging in the polls here.

"I'll take on not just unions and not just the other party, I'll take on my own party establishment, which is what we did in Wisconsin," Walker told reporters.

But the people who really don't like Walker, more so than possibly any other candidate, are liberals, not people in his own party. Union protesters wearing cheese hats heckled Walker while he was speaking on the soapbox, and he was heckled consistently while making his way around the fair. "You suck, Scott Walker!" yelled a man in an Iowa State University hat. "Welcome to Iowa, the union state!"

One protester, Ciara Fox, followed Walker to his media availability and continued heckling him there, asking him why he hasn't visited the family of Dontre Hamilton, a black Milwaukee man who was fatally shot by a police officer. Fox, a certified nurse assistant, said that around 50 SEIU protesters had driven from Milwaukee to protest Walker at the fair.