By John Whitesides
WASHINGTON, Nov 5 (Reuters) - Bitter U.S. political campaigns thundered to a hectic, unpredictable finish on election eve on Monday, as candidates scoured the country for votes in dozens of crucial races that opinion polls showed were still razor-close.
Control of both chambers of the U.S. Congress and 36 governor's offices are up for grabs on Tuesday in an election widely seen as a referendum on the first two years of Republican President Donald Trump's leadership.
In the final stretch, Trump has ramped up his hard-line rhetoric on immigration and cultural issues, including warnings about a caravan of migrants headed to the border with Mexico and "liberal" mobs, and touted a growing U.S. economy that he said would be threatened by Democrats.
He amplified that message with an advertisement linking Democrats and immigrants to violent crime, which aired on NBC on Sunday night. Even fellow Republicans had criticized the spot as racially divisive when it first debuted online last week.
NBC Universal, a unit of Comcast Corp on Monday said it would no longer run the 30-second spot. CNN had earlier refused to run it, calling it "racist."
"After further review we recognize the insensitive nature of the ad and have decided to cease airing it across our properties as soon as possible," a spokesperson for the network said in a email.
Trump planned to spend a final day on the campaign trail on Monday, hitting the Midwestern states of Ohio, Indiana and Missouri at the end of a six-day pre-election sweep focused mostly on competitive U.S. Senate races.
"It's all fragile. Everything I told you about, it can be undone and changed by the Democrats if they get in," Trump told supporters in a conference call on Monday aimed at getting out the vote.
Opinion polls and election forecasters favor Democrats to pick up the minimum of 23 seats they need on Tuesday to capture a majority in the U.S. House of Representatives, which would enable them to stymie Trump's legislative agenda and investigate his administration.
But Republicans are favored to retain their slight majority in the U.S. Senate, currently at two seats, which would let them retain the power to approve U.S. Supreme Court and other judicial nominations on straight party-line votes.
But 75 or more of the 435 House races remain competitive, forecasters said, and control of the Senate is likely to come down to a half-dozen close contests in Arizona, Nevada, Missouri, North Dakota, Indiana and Florida.
Democrats also are threatening to recapture governor's offices in several key battleground states such as Michigan, Wisconsin, Ohio and Pennsylvania, a potential help for the party in those states in the 2020 presidential race.
Trump, who frequently warns of voter fraud and has claimed without evidence that millions of fraudulent votes were cast in 2016, said on Twitter on Monday that law enforcement should be on the lookout for "illegal voting."
Democratic former President Barack Obama delivered donuts to campaign volunteers in a House district in suburban Virginia, where Democrat Jennifer Wexton, a state senator, is challenging Republican incumbent Barbara Comstock in a fiercely contested race.
Obama said the country's character and its commitment to decency and equality are on the ballot on Tuesday.
"All across the country, what I'm seeing is a great awakening," he said. "People woke up and said 'Oh, we can't take this for granted. We've got to fight for this.'"
Trump's polarizing style has spurred record turnout, cranking up enthusiasm in both parties as voters cast ballots to oppose or support the president.
Approximately 40 million early votes – including absentee, vote-by-mail and in-person ballots – will likely be cast by Election Day, according to Michael McDonald, a professor at the University of Florida who tracks the figures. In the last such congressional elections in 2014, there were 27.5 million early votes.
The numbers suggest turnout will be very high for a non-presidential election, McDonald wrote on his U.S. Elections Project website. He estimated turnout would reach 45 percent; that would be the highest for a midterm election in 50 years.
For all Reuters election coverage, see: https://www.reuters.com/politics/election2018
(Additional reporting by Joseph Ax and Kenneth Li in New York and Steve Holland in Washington; Editing by Scott Malone and Jonathan Oatis)
Our Standards: The Thomson Reuters Trust Principles.