Fierce political battles were raging in races across the nation.
With opinion polls showing dozens of tight USA congressional and gubernatorial races in Tuesday's election, the current and former presidents said the results would determine what kind of country Americans live in for the next two years.
In traditionally red Texas, popular Democrat Beto O'Rourke is trying to dethrone Senator Ted Cruz, while Republican Pete Stauber might flip a House Democratic stronghold in Minnesota.
With the election just days away as the poll was conducted, enthusiasm was up among both parties' voters, but Democrats advantage in enthusiasm narrowed to just 4 points: 68% of Democrats and Democratic-leaning independents were enthusiastic about voting, while 64% of Republicans and Republican-leaning independents said the same.
But in the first mid-term under Trump - an utterly unconventional president - there are many unknowns, above all the bottom-line impact of a president who has driven both supporters and foes to a rare fever pitch of emotion.More news: BMW 8 Series Convertible leaks
Midterm elections are often seen as a referendum on the president and there is no shortage of opinions this time around about the current occupant of the White House. But a healthy economy favors the incumbent - and the U.S. economy has been growing with rare vigor.
Anti-Trump Canadians may be breathing a sigh of relief at the prospect, but some Canadian policy experts say a Democratic win is not necessarily better for the Canadian economy or Canadian business.
On the question of whom they would prefer to control Congress, Democrats drew 50 percent of likely voters to Republicans' 43 percent.
But in what could be a sharp warning sign for Republicans, that poll reported college-educated white women - the so-called suburban moms seen as crucial to the 2018 outcome - favor Democrats by a substantial 61 percent to 33 percent.
Obama also condemned Trump's escalating racism going into the midterms.
The president's critics say the highly charged atmosphere he has helped create made the two attackers feel sufficiently comfortable to carry out their crimes.More news: Everton v Brighton: Toffees have the attack to break defensive resistance
Ronna McDaniel, head of the Republican National Committee, said on ABC's "This Week" program that the media had chosen to focus on Trump's immigration rhetoric but the president was also emphasizing economic and job gains under his presidency.
Trump is complaining at a rally in Georgia that "we pay these countries hundreds of millions of dollars" even though "they don't do a damn thing for us". That would allow them to keep the ability to approve "U.S".
Obama meanwhile did what many Democratic candidates have refrained from doing: directly challenging the president.
His predecessor Mr Obama was travelling to Gary, Indiana, on behalf of Senator Joe Donnelly, who faces a stiff challenge from Republican businessman Mike Braun.
Overall, 42% of likely voters say their vote will be to express opposition to the president, while 28% say that it'll be to support him.More news: Why Apple shares are selling off