As Kamala Harris narrows down her choices to be running mate, here is who Republicans REALLY fear on the ticket in the battle with Trump

It is veepstakes season for Democrats as Vice President Kamala Harris looks to find a running mate in the mad-dash before Democrats need to officially nominate their presidential and vice presidential candidates. 

Harris secured enough Democratic delegates to become the presumptive presidential nominee earlier this week, but Democrats have given themselves an August 7 deadline for delegates to vote on the party nominees to make sure they get on the ballot in every state in November.

Roughly a dozen names of prominent Democrats including governors, lawmakers and other officials are included among those being vetted to be Harris' number two. 

But among Republicans, there are several names on the vetting list that they find particularly formidable as the vice president's running mate as she looks to take on Donald Trump this fall. And one name in particular stands out.

Vice President Kamala Harris speaking in Houston on Thursday, July 25. The vice president has less than two weeks to pick a running mate so delegates can meet their August 7 deadline to vote on the ticket

'To be honest, my main reaction to the list that's being vetted is how strong the range of options is,' said Kevin Madden, a Republican strategist and former spokesperson to Mitt Romney's 2012 presidential campaign. 

'Mark Kelly, Josh Shapiro, Roy Cooper, Andy Beshear all bring complementary profiles and skills to the ticket,' Madden said. He said personal relationships an and trust factors should still be the main consideration. 

Republican strategist Matt Wolking believes Shapiro and Kelly are the most formidable candidates in the running for vice president, but he noted choosing Kelly would open up a Senate seat in the battleground state of Arizona should Democrats win the election. 

Democrats might not want to chance that with such a tight Senate majority. 

Multiple Republicans told DailyMail.com they see Pennsylvania Governor Josh Shapiro as a formidable running mate for Vice President Kamala Harris

Other names Republicans mentioned as tough running mates were Senator Kelly, Governor Cooper, Andy Beshear and Governor Whitmer. All have endorsed Harris for president. Whitmer has said while she will work hard to get Harris elected, she's committed to finishing her second term as governor

'I think the game comes down to Michigan and Pennsylvania,' said veteran political strategist Ed Rollins told DailyMail.com.  'You don't win those two, you don't become credible.' 

Rollins, who was behind President Ronald Reagan's reelection campaign, said because of that, Shapiro or Whitmer would both be great choices for Democrats.

'Shapiro is not as experienced, but he knows how to win,' Rollins said. 

'Ever since 40 years ago when I ran Reagan's campaign, Pennsylvania was the last state to come in, so it's a tough state, and it's going to be a tough state again. And if you don't win Pennsylvania, it makes it awful hard to get to 271.' 

'If I were running this campaign, which obviously I am not, I would focus on making it like gubernatorial races in those three or four states that matter,' he added. 

Rollins said putting a battleground state Democratic governor on the ticket wouldn't automatically make a difference, but it would likely be the best choice to help Democrats. 

He pointed out people don't end up voting for the vice president, but it makes a difference at this stage for candidates to pick someone voters believe could be president if something were to happen and that's the ultimate threshold at this time. 

GOP Strategist Scott Jennings agreed. 

'Shapiro.' he responded when asked who would be the most formidable running mate. Why? 'Talent. Pennsylvania,' he added.

But Jennings said there would be another important factor if Harris chooses Shapiro.

'It would be a leadership moment for Harris to tell the rampant anti-Semite and anti-Israel elements of her coalition to pound sand,' he argued. 'I would be impressed if she did.' 

Governor Shapiro with Harris in Philadelphia on July 13. He will be hitting the campaign trail for her in Carlisle, PA on Saturday amid speculation over who she will pick as a running mate

Whether or not Shapiro is the vice president's pick, he's already hitting the campaign trail for the presumptive Democratic presidential nominee. 

On Saturday, the Pennsylvania governor is headed to Carlisle, PA near the State Capitol in Harrisburg to kick off a weekend of action for Democrats to mark 100 days until the election. 

More than 8,000 people in the Keystone state have signed up online to volunteer in the state for Harris since Sunday, according to the campaign. 

Shapiro won the governors race in Pennsylvania in the 2022 midterms with more than 56 percent of the vote. 

In 2020, he ran ahead of Biden when seeking reelection as Attorney General. And in 2016, he won the Attorney General race in the state, despite Trump winning Pennsylvania at the top of the ticket.