The Trump administration has tried a variety of approaches to deter people from trying to reach the United States - most controversially a "zero tolerance" policy of criminally charging every adult migrant who crosses the border illegally, separating parents from their children.
While it's true the underlying laws were the same, the Trump administration mandated anyone caught crossing the border illegally was to be criminally prosecuted.
It was not clear whether the plan would pass legal muster, although Trump, who sought to use immigration as an issue to motivate Republican voters in the 2016 presidential race and now ahead of the November 6 elections, said it would.
It remained unclear whether the first caravan will make a turn east to Mexico City, or try to reach the nearest and most unsafe stretch of border, which lies nearly directly north. Divisions began to appear about what route to take.
Trump had yesterday announced that he plans to automatically deny asylum to migrants who try to enter the US illegally between ports of entry.
The legally binding agreement requires facilities housing detained minors to be run by licensed programmes and provide toilets, drinking water, contact with family, and adequate temperature control and ventilation, among other conditions. If the military's assessment is accurate, it would mean the United States is positioning five soldiers on the border for every one caravan member expected to arrive there.
Writing at Task and objective, retired Col. Paul Yingling, who commanded USA troops in Iraq, cut right to the chase.
He also did not clarify how he wants to detain asylum-seekers, but hinted that he wants to build tent cities and "we're going to hold them right there" without providing details.
On average, once released, an asylum case takes three and half years to complete. Claims have spiked in recent years, and there is now a backlog of more than 800,000 cases pending in immigration court. "They do that with us, they're going to be arrested". The second group includes Hondurans, Salvadorans and some Guatemalans.
Trump has ramped up his tough stance on illegal immigration in recent days. Illegal crossings at the USA southern border have spiked recently, with border patrol agents picking up almost 2,000 people a day trying to enter from Mexico.
"To turn them away with some amorphous instructions is illegal", he said.
Last week, officials indicated that 800 to 1,000 troops might be sent. But official statements suggest at least some of them will be armed.
Perez responded each time by saying that immigration was not the real issue in the election, and that Trump's threats were merely a distraction.
Trump has rejected the idea he has been "fearmongering" and using the issue for political purposes, but his escalating rhetoric in the final days of the campaign season calls that denial into question. And this week he is asserting he could act by executive order to unilaterally end birthright citizenship for the children of non-U.S. citizens.
Trump also tweeted a video Wednesday alleging Democrats were responsible for allowing a homicidal immigrant into the USA but provided no evidence supporting that claim.
Many on social media could not believe that migrants were already taking legal action against the government of a country they had not even entered into yet. It adds: "Democrats let him into our country..."
Fox News' Jennifer Griffin and The Associated Press contributed to this Fox News report, which is used by permission.