Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: A hot dog, Cinderella, a SWAT Team officer and a small Donald Trump attended a Halloween-themed naturalization ceremony overseen by a mini Obama. On Friday, 27 children wore costumes as they took the Oath of Allegiance during their naturalization ceremony near Washington, D.C. Among those in costumes included 10-year-old Germany native Luke Nitschke, dressed as a hot dog, and 12-year-old Ethiopia native Nathnael Asegdew, dressed as President Barack Obama. They, along with the other children, became some of the country's youngest and newest citizens before heading out to go trick-or-treating. Razvan Godja, 13, was also one of 27 children from 19 countries who took part in the special ceremony that was held by US Citizenship and Immigration Services (USCIS) at its Washington field office.On Friday, 27 children wore costumes as they took the Oath of Allegiance during naturalization ceremony near D.C.Other children dressed as Anna from Frozen and Minnie Mouse as USCIS held a special ceremony at Washington field office in Fairfax, VirginiaRazvan Godja, 13, of Romania dressed as Trump and was one of 27 children from 19 countries to participateKids aged seven to 14 got citizenship certificates and took allegiance oath 
 Question:Stopping illegal immigration is a cornerstone of the real _'s presidential campaign.

Donald Trump