(Ross D. Franklin/AP)

The Justice Department has cut off negotiations with Sheriff Joe Arpaio and officials with the Maricopa County, Ariz., Sheriff's Office in its effort to install an independent monitor to rein in the unconstitutional tactics used by officers there.

Arpaio, who calls himself "America's Toughest Sheriff," defied the Justice Department suggestion that it could sue the county and the sheriff's office to force the issue.

"I am the constitutionally and legitimately elected Sheriff and I absolutely refuse to surrender my responsibility to the federal government," he said in a letter the Justice Department today. "And so to the Obama administration, who is attempting to strong arm me into submission only for its political gain, I say, 'This will not happen, not on my watch!'"

In December, the Justice Department released findings in its investigation of Arpaio's office, noting there were significant civil rights violations, including the use of excessive force, and other systemic problems.

The Justice Department said in a letter to Arpaio's attorney today that despite the sheriff's office acknowledging the need for an independent judicial monitor to oversee reforms, "MCSO has now walked back from its agreement."

"DOJ considers the oversight of an independent monitor to be an absolute necessity for meaningful and sustainable reform of MCSO," Roy Austin, the Civil Rights Division's deputy assistant attorney general, wrote to Arpaio's attorney.

"It was disappointing, to say the least, for you to contact us 24 hours before our negotiations were scheduled to continue and raise for the first time, a precondition that you understood would result in the cancellation of negotiations," he wrote.

"We believe that you are wasting time and not negotiating in good faith," he wrote. "Your tactics have required DOJ to squander valuable time and resources. The violations of the Constitution and federal law identified in our December 15 letter have not been meaningfully addressed and continue to negatively impact the lives of all Maricopa County residents."

According to the letter, representatives from the MCSO also canceled a meeting at the last minute on Feb. 27 and took more than two weeks to reschedule the meeting with the Justice Department.

In recent weeks, the sheriff's office has apparently been claiming it needs additional information from the Justice Department in order to reach a settlement.

In the initial Dec. 15, 2011, findings letter, Thomas Perez, the assistant attorney general for the Civil Rights Division,  to Bill Montgomery, the county attorney for Maricopa County.

"MCSO engages in a pattern or practice of unconstitutional policing.  Specifically, we find that MCSO, through the actions of its deputies, supervisory staff, and command staff engages in racial profiling of Latinos; unlawfully stops, detains and arrests Latinos; and unlawfully retaliates against individuals who complain about or criticize MCSO's policies."

The Justice Department's Civil Rights Division has been investigating Arpaio's office since June 2008.  There is also an ongoing criminal investigation into officials at the sheriff's office.

In the letter sent today, the Justice Department said it is moving closer to suing the county and sheriff's office in federal court, in an effort to implement the federal monitor.

"Your decision to raise this again now only serves to delay settlement discussions and to drive us closer to pursuing judicial remedies," the letter said. "MCSO's refusal to engage in good faith negotiations requires us to prepare for civil action."

The sheriff's office said in response that appointing an outside monitor "usurps the powers and duties of an elected sheriff and transfers them to a person or group of persons selected by the federal government … nullifying the authority of the elected Sheriff and eviscerating the will of the citizens of Maricopa County."