Addressing reporters at a breakfast hosted by the Christian Science Monitor, Priebus pointed to Republican victories in last week's special House election in Florida and earlier this year in the San Diego mayor's race as evidence that Obama and the health-care law had nationalized otherwise local races.
"You had the nationalization of Barack Obama and Obamacare in both of those places, and it is a poisonous issue for Democrats, just like there were national issues that really hurt us in 2006 or 2008," Priebus said, a reference to the 2006 midterm cycle when Democrats capitalized on the unpopularity of then-President George W. Bush and the Iraq war to win control of the Senate and House.
Still, Priebus acknowledged that Republican wins in the midterms -- which traditionally attract a smaller and less diverse electorate -- would not necessarily be a harbinger for winning back the White House in 2016.
"We need to, at the RNC, make sure that we can capture the positives and the benefits that we've been able to provide in 2014 and build on that to have success in 2016, which is a very different type of election with different issues that move the electorate at play," Priebus said. "I'm just very mindful of the differences between the two."
Priebus's appearance marked one year since he launched the "Growth and Opportunity Project" -- a blistering assessment of the Republican Party's problems appealing to women and minorities and an ambitious blueprint to transform it into a welcoming home for the rapidly diversifying electorate.
Priebus said after a year of investment, the RNC has scores of staffers across the country doing outreach to minority groups, especially African Americans and Hispanics. He said the party is making inroads appealing to women -- especially single women under age 35, the demographic of women voters that Priebus said has been the most difficult for Republicans to court -- and has overhauled its digital and data operations to catch up to the advances Democrats made during Obama's two presidential campaigns.
"We've fundamentally reshaped the way that we do business at the RNC," Priebus said.
In addition to revamping the party's digital infrastructure and outreach efforts, Priebus said, winning back the White House will require a nominee who has broad appeal to the country's voters. The GOP, he said, should "put a candidate on the ballot that people want to sit down and have a beer with."
Priebus is asserting more control over the nominating process, including restricting the number of debates and influencing the selection of moderators. "We have to make sure that we put together a process and an operation that gives our nominee the best possible platform in order to be successful," he said.
The Democratic National Committee issued a report on what it said was the Republican Party’s “rebrand failure.” DNC Chairwoman Debbie Wasserman Schultz said Republican policies alienate the middle class, women, Latinos, African Americans, gays and lesbians, and young voters.
“What changes we have seen from the Republican Party are superficial and tactical but do little to address their core problem – that they have an out-of-touch agenda that prioritizes opportunity for some instead of opportunity for all,” Wasserman Schultz said in a statement.