There's a disconnect between how Apple CEO Tim Cook sees his company's tax strategies and how some members of the US Senate see it. That became clearer than ever today after Cook and two other Apple executives testified before Congress, explaining why they're holding most of their international income in Irish subsidiaries like Apple Operations International (AOI), which declare no tax residency anywhere in the world.

AOI hasn't filed a tax return anywhere in the world for the last five years, yet it earned $30 billion in income from 2009 to 2012, according to a Senate report released yesterday.

Senator Carl Levin (D-MI), who chairs the Senate subcommittee where Cook testified, opened the proceedings today by suggesting that Apple has avoided paying $9 billion in taxes with strategies like those seen at the Irish subsidiaries.

It wasn't just Levin who hammered Apple over these tax issues, either. Sen. John McCain (R-AZ) noted that 95 percent of Apple's research and development takes place in the US, with less than 1 percent of it in Ireland. "How is it possible that no tax goes to any country?" asked McCain.

Cook described AOI as merely "a holding company" for money earned abroad that has already been taxed in the various countries it was earned in. He also noted that AOI earns investment income, which "is taxed in the US at the 35 percent level."

Beyond that, Cook mostly stuck to talking points that were laid out in interviews he has given over the past several days, noting that his company paid $6 billion in taxes last year and suggesting that the App Store alone has created 300,000 new jobs in the US.

Other than McCain, however, Republicans were more protective of the Apple executives. Sen. Rand Paul (R-KY) in particular lambasted the whole event and was more concerned with government "bullying" than with Apple's tax bill. "I'm offended by a $4 trillion government bullying one of America's greatest success stories," Paul said. He added: "I'm very frustrated by these proceedings... They're just doing what every company does."

In the end, Cook wouldn't agree to move more of Apple's cash to the US while it has a 35 percent corporate tax rate. "I am not proposing a zero rate," said Cook. "My proposal is that we have a reasonable tax for bringing back money from overseas." He called for a "dramatic simplification" of the US tax code.

Apple struck a deal with Ireland in the 1980s that made sure its corporate tax rate there would never be above 2 percent. The US corporate tax rate is ostensibly the world's highest at 35 percent, but after deductions the effective corporate tax is around 12 percent, the lowest it has been in decades.

The hearing ended with some final words from a dissatisfied Levin.

"We've got to change this system. You made a unilateral decision—three Apple employees decided where these profits are going to be taxed or not taxed. Folks, it's not right. That is not right."