WASHINGTON (NewsNation Now) — Tuesday’s election in Georgia may have a profound impact on Joe Biden’s presidency even before he takes the oath of office in just over two weeks.

If the Democrats can control the Senate, it could be relatively smooth sailing for his agenda.

If the Republicans retain control, he could face some very stormy seas.

All the Republicans have to do is win one of the seats being contested to retain Senate control — 51-49 — a position of power that could have big ramifications for the Biden agenda, according to Emory University political scientist Alan Abramowitz.

“I think there is a strong likelihood that a Republican majority led by Mitch McConnell would attempt to obstruct most of Biden’s agenda,” he said.

The president-elect has proposed major initiatives on a number of topics that may wither, he said, if Republicans are in charge because they know their base would rebel if they compromise.

Abramowitz said there might be some cooperation on an infrastructure bill or a scaled-down pandemic relief package, but nothing is certain.

“Given the divisiveness of politics right now, given the degree of polarization that we see, not just in the Senate, but in the country, I think would be very reluctant to go along with much of Biden’s agenda,” Abramowitz said.

watch: NewsNation’s Marni Hughes talks with political science professor Tammy Greer, Ph.D. about the GA runoff election

A Republican majority could also spell trouble for Biden’s judicial nominations and even his cabinet, both of which require Senate confirmation,

“I think some of them could find themselves in trouble. We know that some of the people that Biden has already nominated are not popular with Republicans,” he said.

But a president has many tools, including executive orders, to fight obstructionists.

“I think what you’re going to see in the first days of a Biden administration in any event is that he’s gotta very quickly reverse a lot of the executive orders that were put in place by President Trump,” he said. “That’s something he can do very quickly, very dramatically.”

If the Democrats win big on Tuesday in Georgia and wind up in control of the Senate, a President Biden can be expected to move quickly on an agenda that includes a much larger pandemic relief package, new action to address climate change, racial justice reforms and higher taxes on the wealthy.

Biden spent decades in the Senate and knows what it takes to make it work. This week, he’s going to find out just how hard his job will be to get something done.