U.S. Vice President Kamala Harris and former President Donald Trump waited Wednesday to find out which one of them will be the country’s next president, as election officials in several key states worked to complete the vote count in what has been a tight presidential race.

In the U.S. system where the presidential election is tallied in a series of state-by-state contests, both Harris and Trump were quickly declared winners in states where their parties enjoy clear majority support, while the nation focused on roughly seven so-called battleground states that were expected to tip the balance in the direction of the winner.

Several of those closely watched states remained uncalled early Wednesday, including Michigan, Wisconsin, Nevada, Arizona and Pennsylvania.

Trump won Georgia and North Carolina.

A Harris campaign official told a crowd of her supporters in Washington that she would not address the gathering overnight but would speak later Wednesday.

The state-by-state electoral system includes different rules for how and when votes are counted, adding to the complexity of how results are reported.

In some states, ballots that are cast in-person before election day, or by mail, were allowed to be counted as they came in, leading to faster results. But in some states, those counts did not begin until polls closed Tuesday night, while some states also allowed ballots to be put in the mail as late as Tuesday, meaning final results in those areas will not come for days.

In the last election, in 2020, President Joe Biden was not declared the winner until four days after Election Day, when the results for the state of Pennsylvania gave him more than the 270 electoral votes (out of 538) necessary for victory.

"Pennsylvania could take as much as a week. But it may or may not be the decisive state,” Elaine Kamarck, senior fellow at the Brookings Institution, told VOA. “If she (Harris) picks up North Carolina, for instance, then it may not matter so much. And North Carolina and Nevada, it may not matter that much. So, it kind of depends on what happens in the rest of the night as to how long we'll have to wait to see if a president is elected."

In Congress, the Republican Party took control of the Senate. Despite a few races still too close to call, the Republicans took a 51-seat advantage in the 100-member chamber late Tuesday. There were still too many races to know which party would control the U.S. House.

Looming over the eventual result was the prospect of legal challenges. Both the Trump and Harris campaigns were ready with legal experts to contest any irregularities they saw.

A Harris win would make her the country’s first female president. A Trump victory would make him the first U.S. leader since Grover Cleveland in the 1880s to serve non-consecutive terms.

The next president is set to be inaugurated for their four-year term on January 20.

A key foreign policy focus in either a Trump or Harris administration will be relations between the United States and China, including subjects such as trade, Taiwan and China’s actions in the South China Sea.

Vincent Wang, dean of the college of arts and sciences at Adelphi University, told VOA Mandarin that China would approach the prospective presidents differently, including being potentially more aggressive toward the United States if Harris wins.

"China may create some events to give her (Harris) a show of force," Wang said.

"After all, the United States is tied up with wars in the Ukraine, and in Israel and Gaza. In the Taiwan Strait, China has already carried out so-called gray area strategy on a daily basis. I think China may expand its gray area strategy closer to Taiwan as a way to a test Harris."

"If Trump is elected, I think China may not dare, because he doesn't go through drafts, he has already said harsh words. If he wakes up today, he might say he's going to raise tariffs by 200%. If he wakes up tomorrow, he might want to bomb Beijing. So I think this so-called this Trump-type deterrent, on the contrary, will make them a little bit more restrained."