The Hillary ClintonHillary Diane Rodham ClintonTrump thanks 'vicious young Socialist Congresswomen' for his poll numbers Will Trump's racist tweets backfire? Democrats fret over Trump cash machine MORE campaign slammed Donald TrumpDonald John TrumpPompeo changes staff for Russia meeting after concerns raised about top negotiator's ties: report House unravels with rise of 'Les Enfants Terrible' Ben Carson: Trump is not a racist and his comments were not racist MORE's running mate, Mike Pence, as divisive and unpopular moments after the presumptive Republican presidential nominee made the announcement. 

“By picking Mike Pence as his running mate, Donald Trump has doubled down on some of his most disturbing beliefs by choosing an incredibly divisive and unpopular running mate known for supporting discriminatory politics and failed economic policies that favor millionaires and corporations over working families,” campaign chairman John Podesta said in a statement. 

After days of speculation, Trump announced on Twitter he had picked the first-term Republican governor from Indiana as his running mate. A formal news conference will follow Saturday at 11 a.m., he tweeted. 

Pence had been on a final shortlist for the spot along with former Speaker Newt Gingrich (Ga.) and New Jersey Gov. Chris Christie, according to Trump. 
 
In picking Pence, Trump is selecting a candidate who could improve his conservative bona fides and help appeal to the party's base.
 
At the same time, privately those in Clinton World said the Pence pick shows a new level of seriousness for the Trump campaign. 

"I think it shows he's (maybe) getting serious about running for President," one longtime Clinton adviser said in an email. "We'll see how long that lasts but I'd put this in the side of the ledger where the professionals in the process got their way." 

Another friend of Clinton's said the preference among most Clintonites probably would have been for Christie or Gingrich. "They're way more colorful." 

But one Clinton aide said while Pence lacks the name recognition and outsized personalities of Christie and Gingrich, he comes with his own problems. 

"Trump is so far down in the negatives that even if Pence brought a ton of positives to the table that doesn't get Trump anywhere close ... let alone back on track," the aide said. "It'll be very interesting to see how they get on the same page where there are disagreements." 

The aide pointed to the difference of opinion between Trump's opinion on banning Muslims from entering the country and Pence's stance. 

Taking to Twitter last December, Pence wrote, "Calls to ban Muslims from entering the U.S. are offensive and unconstitutional." 

The Clinton campaign on Friday quickly raised one of the most controversial moments of Pence's tenure as governor: His handling of a religious freedom law.
 
Pence's signature on the law in 2015 resulted in nationwide backlash and several companies boycotted the state. The law was later amended to clarify it doesn't allow discrimination against gay people. 

“Pence is the most extreme pick in a generation and was one of the earliest advocates for the Tea Party. He was the first of GOP leadership to join Michele BachmannMichele Marie BachmannKlobuchar urges CNN town hall audience: 'That's when you guys are supposed to cheer, OK?' Michele Bachmann praises Trump: Americans will 'never see a more godly, biblical president' Will Biden lead a 'return to normalcy' in 2020? MORE’s Tea Party Caucus.  As governor, Pence personally spearheaded an anti-LGBT law that legalized discrimination against the LGBT community, alienated businesses, caused boycotts, lost investments and embarrassed Hoosiers — a law he was later forced to revise." 

"Pence also personally led the fight to defund Planned Parenthood while serving in the House and fought to pass Indiana's 2016 anti-abortion law, with some of the most outrageous restrictions in the country that threatened women’s privacy and limited their choice. And just like Trump, he’s been a long-time opponent of comprehensive immigration reform," Podesta wrote. 
 
Podesta then called Pence bad for the economy, claiming he opposes raising the federal minimum wage. 
 
“Voters deserve better than more of their divisive policies and ‘me-first’ economic proposals. This new Trump-Pence ticket stands in dramatic contrast to Hillary Clinton’s vision of our future — one where we are stronger together, where unity prevails over division and the economy works for all Americans, not just those at the top.”
 
In an online video released shortly after Trump's announcement, the Clinton campaign slammed the governor for the controversial stances he's taken on social issues. 
 
 
 
The video also dug up footage of Pence saying, while he was a congressman, that he was willing to "shut down" the government to defund Planned Parenthood.
 
The video concluded: "Pence is bad for women's health. He's bad for immigrants," and he and Trump would "build a great, big, beautiful wall between America and progress."  
 
Updated at 11:58 a.m.