... do you believe the invitation was negotiated beforehand, or that it came as a complete surprise to Trump?

Bad call on Peña Nieto's part.

He probably anticipated HRC would accept and DT would tell him to go fuck himself.

but the Trump campaign claims that there were negotiations for several days before the visit

saying the President of Mexico has a real estate scandal of his own in Mexico . Started surfing a bit ago ran across this
article . Makes me wonder if today 's visit was an invitation from Mexico or did it start with Don 's campaign . I do not
know , does Don know the contractor involved ?

"After years of demonstrations and court battles, President Enrique Peña Nieto signed an executive order this month expropriating 91 acres of what many here consider sacred land. And is it any wonder he did, residents argue. The same contractor carving through their land has held the title to the president’s family mansion, provided a house to the finance minister for zero profit and does billions of dollars in deals with the government.

“We knew the president’s political grip in this state goes back for years and years,” Mr. García said. “We just didn’t know it would end up affecting us directly, so badly.”

Mr. Peña Nieto’s relationship with the contractor is one of several recent scandals that have raised tough questions for the president, tainting his legacy and further eroding the public’s already shaky faith in the country’s governing institutions. "

"Residents in the path of the highway say their battle against the government raises troubling questions, too. How did a friend of the president’s who started out selling office supplies like Post-it notes wind up running an empire that collects billions of dollars in government contracts, getting the green light to pave through a protected forest and winning bids to build hospitals and trains?"

Rest of article http://www.nytimes.com/2015/07/31/world/americas/mexican-presidents-ties-to-contractor-raise-questions.html?_r=0