TAMPA, Fla. — As he continued his effort to turn the public’s attention to the rise in federal spending, Mitt Romney acknowledged Wednesday that President George W. Bush presided over the accumulation of $4 trillion in debt, but faulted President Barack Obama for failing to do enough to stem the growth in spending.

Romney noted that Obama was a harsh critic of Bush’s spending policies during the 2008 campaign, calling his record on debt “irresponsible.” But without delving into the complexities of the economic collapse that Obama faced after taking office, he charged that the President did not fulfill a promise to cut the debt in half: “Instead he doubled it, all right, he doubled it,” the former Massachusetts governor said.

“It’s true you can’t blame one party or the other for all the debts this country has, because both parties in my opinion have spent too much and borrowed too much when they were in power,” Romney told a crowd of several hundred people who cheered enthusiastically throughout his speech. But, he added, “I find it incomprehensible that a President could come to office and call his predecessor’s record irresponsible and unpatriotic and then do almost nothing to fix it, and instead every year to add more and more and more spending.

“If I’m President, I’m actually going to take responsibility and lead, and get us on track to have a balanced budget.”

In his indictment of Obama’s handling of the economy —paign — Romney often prefaces his statements by saying that Obama was not responsible for the nation’s economic crisis, but accuses him of making it worse. He rarely discusses his views on how the Bush administration’s policies contributed to the nation’s fiscal crisis or more specifically the Wall Street meltdown. On Wednesday he did not even mention Bush’s name, repeatedly referring to him as the “predecessor.”

Romney has a warm friendship with President George H.W. Bush and his wife Barbara, who offered a warm endorsement of the candidate in late March. But his campaign did not send out a statement acknowledging the 43rd president’s informal endorsement of Romney on Tuesday. The younger Bush told an ABC News reporter “I’m for Mitt Romney” _ and did not elaborate _ while entering an elevator during a visit to Washington on Tuesday.

Bush’s record, particularly on spending issues and the costly wars in Iraq and Afghanistan, is unpopular even within his own party _ one reason why Romney rarely mentions his name. (When Bush left office in January of 2009, only 37 percent of adults said they had a favorable view of him). The Obama campaign has tried to tie Romney’s policies to those of the 43rd president at every turn.

By focusing on the national debt and spending issues in Florida, Romney is targeting not just Republicans, but also independents key to defeating Obama, who won the state by a thin margin in 2008. On Wednesday in St. Petersburg, Romney urged members of the audience to “go out and talk to your friends and get them to lean this way as well.”

“There are a lot of people who haven’t heard from us. We need to get to the college kids, for instance, and people coming out of high school, and folks that have only lived in Florida for short while.”

The candidate suggested a possible pitch to the unpersuaded: “Say, ‘Guys, did you know there’s about a half million dollars that this government has in debt and obligations on your household? And this president keeps spending more and more, and hiding from you what’s going on. We’ve got to get this guy Romney in there so we can have a brighter future for ourselves; create jobs and have a brighter future for our kids.’”