Bloomberg says in the ad that the nation needs to support Democrats to "send a signal to Republicans in Washington that they have failed to lead, failed to find solutions, and failed to bring us together".
Trump has not remained silent about the former president though. On Friday, he condemned Trump's "fear-mongering" and what he said was a disdain for the truth.
"This election will decide whether we build on this extraordinary prosperity we have created", he added. The two states each have crucial governor's races with progressive, African American Democrats - Georgia's Stacey Abrams and Florida's Andrew Gillum - running against two staunch Trump allies, Georgia Secretary of State Brian Kemp and former Florida Rep. Ron DeSantis.
Trump has punched back, accusing Obama of leaving behind a trail of broken promises on trade, the economic recovery and a promise during his presidency that patients could keep their doctors under his health care law.
The ad is among several on Facebook saying that Braun used to be a Democrat and has voted for tax increases as a member of the state Legislature.
"This Tuesday I need the people of IN to send a message to Chuck Schumer, Nancy Pelosi, Maxine Waters and the radical Democrats by voting for Mike Braun", Trump said as the crowd erupted IN boos.
US Senator Chris Van Hollen, who heads the Democratic Senate campaign arm, said it was "remarkable" that Democrats were even in striking distance of capturing the Senate given the unfavourable map they faced. That would allow them to keep the ability to approve "U.S".
"I've been involved in scores of conversations about stopping illegal immigration from Mexico and never once has there been a discussion of the political impact in USA domestic politics", Pompeo said.
'A vote for Democrats is a vote to liquidate America's borders.
But the president - to the unease of some in the party - has instead used his almost nonstop schedule of campaign rallies to keep the spotlight on what he calls the security threat from migrants seeking to enter the USA through Mexico. Trump has also announced plans to try to end the constitutionally protected right of birthright citizenship for all children born in the U.S.
Republicans are favoured to retain their slight majority in the US Senate, now at two seats, which would let them retain the power to approve US Supreme Court and other judicial nominations on straight party-line votes. He later added: "We don't want to go back to the Obama days".
Mr. Van Hollen, meanwhile, said Mr. Trump's strident style is keeping his red state incumbents in the game, while giving Democratic challengers in places such as Texas, Tennessee, Arizona and Nevada a shot. Republican National Committee Chairwoman Ronna McDaniel pointed to the recent October jobs report as evidence Republicans are delivering.
"The fact we still have a narrow path to a majority is a sea change from where we were 2 years ago", he said on ABC. "We need to get him back", Booker said. He appeared on "Fox News Sunday".
The president said the main focus of his campaigning is on the Senate, while talking to reporters on the White House lawn Sunday.
The Virginia Democrat faulted the White House for opposing an election security bill that would have ensured that every polling station had a paper ballot to audit after the election.
Trump's job approval rating is basically unchanged from last month's poll among likely voters.