Donald Trump went after Sen. Bernie Sanders at a rally Wednesday in Virginia, branding the Vermont senator a "maniac" and a "communist." 

Trump said he watched in Tuesday night's first Democratic debate as Hillary Clinton and Sanders each vowed to give things away if they're elected. 

"I watched Hillary last night with, ‘we’re gonna give this, we’re gonna give that, we’re gonna give that.' The poor woman. She's gotta give everything away because this maniac that was standing on her right was giving everything away, so she’s following! That's what's happening," he said. 

Trump went on to refer to Sanders as a "socialist-slash-communist," adding that nobody wants to use the word "communist" to describe Sanders.

"He's gonna tax you people at 90 percent; he's gonna take everything. And nobody's heard the term 'communist.' I call him a socialist-slash-communist because that's what he is."

In new polls, Trump leads Ben Carson by sizable margins in Nevada and South Carolina, two key early-voting states. 

Fox News contributor Byron York reacted to the new numbers this morning, saying that the first four states - Iowa, New Hampshire, Nevada and South Carolina - are likely to decide the GOP nominee.

According to Real Clear Politics, Trump leads by 13 points in New Hampshire, and has a five-point lead in Iowa.

York said Trump appears to be in a "very strong position right now," leading in all different parts of the country and drawing the biggest crowds by far.

He also noted that Trump has used media appearances "brilliantly," allowing him to retain his lead while spending just $2 million to this point.

By comparison, Hillary Clinton spent more than $18 million through July, while Ben Carson and Ted Cruz each spent more than $5 million.

Watch the segment above from "America's Newsroom."