Sen. John McCain (R-Ariz.) is promising that starting next year, the Republican-led Senate will conduct much tougher oversight of the Department of Veterans Affairs, which McCain said has failed to implement a new law aimed at bringing accountability to the broken department.

"It's been a significant disappointment to me," he said in a Thursday interview with TheBlaze. "We are going to have to have a lot more vigorous congressional oversight."

Sen. John McCain (R-Ariz.) told TheBlaze that a GOP-led Senate will mean much tougher oversight of the Department of Veterans Affairs. (T.J. Kirkpatrick/Getty Images)

McCain said it's widely expected that Sen. Johnny Isakson (R-Ga.) will be the chairman of the Senate Veterans' Affairs Committee when Republicans take over the chamber next year. He also said he's already talked with Isakson about the need to crack down on the VA.

"He's going to start up the hearings right away about what's happened with the bill, what hasn't happened, and frankly, he's going to have to put their feet to the fire," McCain said.

McCain and other members of Congress have been increasingly critical of the VA for its failure to fire anyone involved in the VA health care scandal. Earlier this year, Congress passed a bill giving the VA secretary the authority to fire people, but Secretary Robert McDonald appears to have used it just once.

Last week, the VA finally fired one official in Alabama involved in the scandal, but that official has the right to a three-week appeal process under the law.

A few other officials, however, have been allowed to retire, a problem that McCain has raised in two letters to McDonald. As of late October, McDonald had not replied to either of McCain's letters.

McCain told TheBlaze late Thursday that McDonald had finally replied in a three-page letter that McCain characterized as "very defensive." He said his staff is still analyzing the letter and considering how to respond.

McCain agreed that given the systemic problems the VA had in delaying care to veterans and covering up the problem, the VA needs to fire people immediately in order to effect change.

"The only conclusion that people who are there would draw is, it's business as usual," he said of the lack of firings so far.

McCain predicted that Republican leadership in the Senate next year would lead to much tougher oversight than what's been seen under Democrats. He said that while current Veterans' Affairs Committee Chairman Sen. Bernie Sanders (I-Vt.) cares about veterans, Sanders "believes that spending more money and hiring more people is largely the answer."

But after several months, McCain said it's clear that Secretary McDonald will spend the money Congress provided, but has not implemented the oversight provisions of the bill.

"We did give him the various authorities, and it hasn't happened," McCain said.