Mr. Cook isn't going to Washington, but his top lawyer is.
Apple's general counsel, Bruce Sewell, will speak on behalf of the iPhone maker and CEO Tim Cook on Tuesday at a hearing before the Senate Judiciary Committee on the balance between national security and individual privacy.
At the same time, Apple filed a motion asking the courts to vacate a judge's February 16 order requiring Apple to help the FBI access a terrorist's iPhone, contending the order violates the company's constitutional rights.
"This is not about one isolated iPhone," said the tech giant in the 65-page document. "Rather, this case is about the Department of Justice and the FBI seeking through the courts a dangerous power that Congress and the American people have withheld: the ability to force companies like Apple to undermine the basic security and privacy interests of hundreds of millions of individuals around the globe."
It's the latest move as both Apple and law enforcement escalate their respective agendas. The FBI wants Apple to create a special version of its mobile software to help access data on an iPhone used by a terrorist who, along with his wife, killed 14 people and wounded 20 others last December in San Bernardino, California. The FBI wants to make multiple attempts to unlock the phone, without tripping security settings that would erase the data after 10 unsuccessful tries. Apple, which said it has already helped the FBI as much as it can, contends the court doesn't have the authority to force the company to write a special version of the software.
A judge will need to determine it the government's request to Apple is reasonable, said Harvey Rishikof, a Washington D.C.-based attorney who chairs an American Bar Association's committee on law and national security.
In Apple's court filing Thursday, user privacy manager Erik Neuenschwander estimated that fulfilling a judge's order to create a "back door" into the iPhone would take six to 10 engineers and employees putting in "a very substantial portion of their time" over two to four weeks. "These individuals would otherwise performing engineering tasks related to Apple's products," he said.
"It may come down to a judge deciding if those steps are overly burdensome," Rishikof said.
No court has granted the government the power to force people to weaken the protections on their computers, an Apple executive said on a conference call Thursday. In addition, the government has been hesitant to force citizens to decrypt their devices. Apple's executives now argue that this issue should be decided by lawmakers.
The hearing next Tuesday, titled "The Encryption Tightrope: Balancing Americans' Security and Privacy," will also include testimony from FBI Director James Comey and District Attorney for New York County Cyrus Vance Jr. It will begin at 1 p.m. ET.
"As technology companies have made great strides to enhance the security of Americans' personal and private information, law enforcement agencies face new challenges when attempting to access encrypted information," Committee Chairman Bob Goodlatte (R-Va.) and Ranking Member John Conyers (D-Mich.) said in a joint statement.
"Americans have a right to strong privacy protections," said Goodlatte and Conyers, "and Congress should fully examine the issue to be sure those are in place while finding ways to help law enforcement fight crime and keep us safe."
Apple's Cook, meanwhile, has waged a public campaign against the court's order, saying it could endanger the privacy protections on hundreds of millions of its devices. The company wants Congress, not the courts, to be the ultimate decision makers.
"It should be done all in the open for people so their voices can be heard through their representatives in Congress," Cook said in an interview with ABC News that aired Wednesday. Cook also said he plans to speak with President Barack Obama, but he didn't say when.
An FBI spokesman did not immediately respond to a request for comment.
The battle between the world's most valuable company and the world's most powerful government has become a flash point in the debate over privacy in the Digital Age. Billions of devices have been connected to the Internet over the past several years, including phones that power apps containing financial and medical information. Mobile phones have become the key way people access services ranging from news sites to social networks to bank accounts.
Several of the most powerful figures in the technology industry have spoken out in Apple's defense, including Facebook CEO Mark Zuckerberg, Twitter CEO Jack Dorsey and Google CEO Sundar Pichai, whose Android mobile software is used on most of the world's phones. Microsoft has indicated that it plans to back Apple in a court filing. Tech heavyweights Facebook, Google and Twitter also plan to file an amicus brief in support of Apple.
An Apple executive, speaking to reporters Thursday, said many more companies and special interests will likely file their opinions with the United States District Court's Central District of California Eastern Division, which is hearing the case.
Updated at 3 p.m. PT with quote from the filing and attorney's comments.
CNET's Terry Collins contributed to this report.