From a border wall to a Muslim ban, President-elect Donald Trump's proposed policies stirred up his base and struck fear in others.

But will any of it actually happen?

"We will build a great wall along the southern border," said Donald Trump during a campaign appearance earlier this year.

The proposed wall was a hallmark of his stump speeches.

But the project that could cost up to $25 billion, according to a Washington Post study.

"The wall is effectively a non-starter for most people in Congress," said University of Houston political science professor Brandon Rottinghaus. "Even amongst his party, people know this is not going to happen."

Rottinghaus' research area is the presidency.

"And even if it could happen, the money isn't there to make it happen," said Rottinghaus.

He says most presidents accomplish only about half of their agenda.

Trump's may be more difficult given its divisive nature.

That includes the wall, so-called "extreme vetting" of Muslim immigrants and mass deportations of others.

"You're going to have people who are going to protest this in very vociferous ways," said Rottinghaus. "So, even if it was something he was willing to do in the slightest way, you're going to see a tremendous amount of resistance."

He says Trump can expect continued resistance from Democrats and many fellow Republicans and will likely accomplish little on his own.

"This election, this electorate wanted something big, something different," said Rottinghaus. "And unilateral action that takes baby steps toward that is not going to get it done."

He considers Trump's election night speech an indication of how the president-elect may be willing to budge.

There was some news regarding Trump's wall on Wednesday.

Mexico's president tweeted he's willing to work with America's new leader.

However, the nation's foreign minister reiterated Mexico will not be paying for any wall.