Two leading Republicans shy away from role of Trump VP pick
Sen. Joni Ernst (R-IA) delivers the GOP response to the State of the Union address [YouTube]

Republican Donald Trump's list of potential vice presidential candidates got a little shorter on Wednesday when one prominent U.S. senator withdrew from consideration and a second said she wanted to focus on her home state.

The moves by Bob Corker of Tennessee and Joni Ernst of Iowa could complicate Trump's efforts to rally establishment Republicans behind his presidential bid.

With Trump looking at a self-imposed July 15 deadline to announce his pick, there was no indication that the wealthy businessman was anywhere close to reaching what is perhaps the most important decision he will make as the presumptive Republican nominee.

In New York, Trump met with a potential candidate, Republican veteran Newt Gingrich, and told Fox News he has 10 candidates on his list, including two generals.

One source said Indiana Governor Mike Pence is being pushed internally by some members of Trump's inner circle. A former congressman, Pence met with Trump on Saturday.

Corker, a Tennessee senator who is chairman of the Senate Foreign Relations Committee, had privately wrestled with whether to be a contender for the No. 2 position, telling friends he had never been a surrogate for another politician.

Corker, who spent eight hours at Trump Tower on Tuesday then campaigned with Trump in Raleigh, North Carolina, told reporters he withdrew because "I just felt like I was far more suited for other types of service."

"You know, it’s a highly political role for the next four months,” he said. “I view myself as deep in substance and policy, and I just think there are better ways for me to serve in the public arena."

A fairly vocal supporter of Trump, Corker has not shied away from criticizing some of Trump's bellicose rhetoric. His withdrawal takes away an important party establishment figure as Trump tries to broaden his appeal with plans to visit Republicans in the Senate and House of Representatives on Capitol Hill on Thursday.

"Corker's withdrawal could be considered a canary in the coal mine with establishment Republicans who are convinced that Trump cannot stay on message and can't stay focused on attacking (Democrat) Hillary Clinton without doing some type of damage to his campaign," said Republican strategist Ron Bonjean.

Some Republicans felt Trump erred by not taking full political advantage of FBI Director James Comey statement on Tuesday that Clinton was "extremely careless" with classified emails.

In Raleigh, Trump sharply attacked Clinton but strayed from the message by saying the late Iraqi leader Saddam Hussein had done a good job cracking down on militants.

Trump has been spending time with potential running mates to get a feel for them. One of his most loyal supporters has been Gingrich, the former speaker of the House of Representatives who has been an influential adviser to Trump.

Gingrich was to campaign with Trump on Wednesday night in Cincinnati, Ohio. Some in the Trump camp feel Gingrich would be the best choice.

Ernst, a rising figure in the Republican Party, spent part of the Fourth of July holiday meeting with Trump.

She seemed to be leaning against the vice presidential position, and told Politico, "I made that very clear to him that I’m focused on Iowa. I feel that I have a lot more to do in the United States Senate. And Iowa is where my heart is."

(Reporting by Susan Cornwell and Steve Holland; Editing by Toni Reinhold and Tom Brown)