As a New York real estate mogul isolated in his cluttered office or in his extravagant, Napoleon-like penthouse high atop Trump Tower in Manhattan, Donald Trump could get away with saying almost anything without any real consequences. His thoughts and opinions were always out there, but never taken too seriously. After all he was just a reality television star and president of his own real estate company.

But winning the election, all this has changed. The stakes are higher, and for the first time, his words have consequences -- big consequences. This Sunday's election in the State of Mexico is only the beginning. The impact of his rhetoric towards Mexico, our second-largest trading partner will be a big test for his young presidency.

When Donald Trump announced that he was running for president back in June of 2015, he created quite a stir by his divisive, uninformed, and undisciplined rhetoric towards Mexico and Mexicans:

When Mexico sends its people, they're not sending the best. They're not sending you, they're sending people that have lots of problems and they're bringing those problems. They're bringing drugs, they're bringing crime. They're rapists and some, I assume, are good people, but I speak to border guards and they're telling us what we're getting.

He also pledged to build a big wall along the border with Mexico, which Mexico would pay for.

I would build a Great Wall, and nobody builds walls better than me, believe me, and I'll build them very inexpensively. I will build a great, great wall on our southern border and I will have Mexico pay for that wall, mark my words.

But Trump hasn't always had a contentious relationship with Mexico. In fact, some of the suits from his Donald J. Trump Collection are made in Mexico. And in 2006 he tried building a Trump Hotel and Resort in Baja, Mexico. But with economic trouble on the horizon in 2009, Trump and his partners decided to abandon the project, leaving his buyers feeling betrayed and angry.

This Sunday, the State of Mexico -- the largest of Mexico's 32 states -- will have their gubernatorial election, and Trump's divisive rhetoric towards Mexico is what every voter will be thinking about as they prepare to head to the polls.

The race is between Deflina Gomez, a member of the National Regeneration Movement (MORENA -- which is led by Andres Manuel Lopez Obrador, a far-left, anti-American and presidential candidate), and Alfredo del Mazo (a member of President Pena Nieto's Institutional Revolutionary Party -- PRI) will be closely watched throughout all of Mexico and the rest of the world.

The PRI has been the governing party in the State of Mexico for nearly 90 years. But for the very first time, PRI is in danger of losing the gubernatorial election. The Trump backlash is in full force, and political observers worry that a Gomez win on Sunday will almost guarantee an Obrador victory in Mexico's presidential election in 2018.

2018 will be Obrador's third attempt at running for president. In 2007, after his loss to president-elect Felipe Calderon by a razor-thin margin, he refused to concede claiming election fraud, held rallies across the country, and referred to himself as the legitimate president of Mexico.

A hero of the poor and unabashed political outsider, he is often referred to as a Hugo Chavez-wannabe, the late president of Venezuela. He also has an affinity for dictators and he views the U.S. as an enemy. He even tells the poor that their lives will dramatically improve once he's elected president, and he's known to drive around the streets handing out money.

Feeding off the anti-Trump rhetoric, Obrador is optimistic about Sunday's results. And if Trump continues to insult Mexico with his talk about a wall and making Mexico pay for it, Obrador will feel optimistic about his chances in 2018 as well.

There isn't a president of the universe, but the closest thing to it is president of the U.S. What Trump says and does influences the rest of the world, even elections. Now more than ever, Trump needs to insert some level of discipline into his presidency. Billions of dollars and millions of jobs are now at stake, and for the first time in our lifetime, we risk losing a cherished friend, ally, and neighbor in Mexico. He's built the most beautiful buildings in the world, let's hope he can build a bridge as well.

Mark Vargas (@MarkAVargas) is a contributor to the Washington Examiner's Beltway Confidential blog. He is co-founder and president of tech startup Licentiam. From 2007-2010, he served as a civilian within the Office of the Secretary of Defense.

If you would like to write an op-ed for the Washington Examiner, please read our guidelines on submissions here.