Warner is the most popular politician in the state, polls show, largely because of his centrist, business-focused reputation. Kaine has sought to build a similar reputation, and Warner's multi-city tour of small business around the state seemed design to reinforce that image.

"I'm here with my friend Tim KaineTimothy (Tim) Michael KaineKoch brothers group won't back Stewart in Virginia Kaine shares photos of child detention facility: ‘The real Trump Hotel’ GOP senator: Family separation policy 'inconsistent' with American values MORE because while we've made great progress in Virginia, we need to see the same kind of progress at the national level," Warner said at the beginning of his speech.

Warner later took a veiled shot at Allen. "At the end of the day it's less about Democrat-Republican, it's more about future-past … not about blaming other sides or other people but getting stuff done."

It wasn't until reporters asked Kaine after the event about differences between his economic plan and Allen's that he mentioned the former senator.

After saying his policies focused more on research and development and attracting talent, Kaine went after Allen's energy policies.

"There are many differences between us on energy policy. I'm an 'all of the above' guy. He says he's all of the above but he ridicules anything that's new technology: Solar, wind, thermal," Kaine said. "He has a long track record of ridiculing new technologies and making fun of them — new energy like OPower. It is a massive, $2.3 trillion dollar global industry, and we should be leaders in it and not ridicule it."

Allen's campaign circulated a memo Wednesday attacking Kaine's plan.

"If Chairman Kaine is serious about creating jobs he should support the repeal of Obamacare, work to unleash all of our American energy resources, stop the Obama Administration’s attack on coal and approve the Keystone pipeline," Allen campaign manager Mike Thomas said in a statement. "Virginians deserves a Senator who will stand up for Virginia families and small businesses against the harmful Washington policies that will have will have them paying higher taxes, higher prices for fuel, food and electricity and putting our country in more dangerous debt."

Kaine says he supports the pipeline but thinks it needs more environmental review. As governor he backed the opening of a large coal plant in western Virginia, which angered liberals at the time.

During his speech he also defended President Obama's healthcare reform law, saying that if opponents sought to repeal the entire bill "I'm going to fight."

When The Hill asked what would happen if the Supreme Court struck down the law's individual mandate but let the law stand, he said that "We'll have to dig into it," and emphasized future changes encouraging cost control like paying for healthcare outcomes rather than for tests, but didn't say whether the bill could function without driving up costs severely if the mandate is struck down.