Attorney General Eric Holder maintained Tuesday that he has a “vast amount” of discretion in how the Justice Department prosecutes federal law.

Holder’s remarks, during testimony before the House Judiciary Committee, came in response to GOP accusations that he is flouting the law with his department’s positions on marijuana legalization, criminal sentencing and a contentious provision of the president’s signature healthcare law.

Leading the questioning was House Judiciary Committee Chairman Bob Goodlatte (R-Va.), who asked Holder whether he believed there were any limits to the administration’s prosecutorial discretion.

“There is a vast amount of discretion that a president has — and, more specifically, that an attorney general has,” Holder responded. “But that discretion has to be used in an appropriate way so that your acting consistent with the aims of the statute but at the same time making sure that you are acting in a way that is consistent with our values, consistent with the Constitution and protecting the American people.”

Holder said the Justice Department must defend federal laws on the books unless it concludes that “there is no basis to defend the statute.”

He cited, for example, the administration’s decision no longer to defend the Defense of Marriage Act (DOMA), which prohibited same-sex couples from receiving certain federal benefits. That position, Holder noted, was upheld by the Supreme Court, which later struck down main provisions of the statute.

Republicans on the panel argued, however, that the Obama administration has gone to unprecedented lengths in its liberal use of discretion on several fronts.

“All of this demonstrates a pattern on the part of the Obama administration to ignore or rewrite the very legislation that places limits on the executive branch authority, for purely political purposes,” Goodlatte said.

Historically, the boundaries of prosecutorial discretion are murky, making it difficult for the administration’s critics to say Holder or President Obama has crossed them, UCLA law professor Adam Winkler said.

But, more than its predecessors, the Obama administration has used prosecutorial discretion on some of the day’s most divisive issues, inviting criticism from his opponents on the other end of Pennsylvania Avenue, Winkler said.

He cited the DOMA stance and the administration’s decision to halt deportations of many illegal immigrants, among other cases.

“This administration has gotten into hot water because it has used prosecutorial discretion in high profile, controversial areas,” Winker said.

On Tuesday, Republicans also grilled Holder on the Obama administration’s decision not to interfere with marijuana legalization efforts in Colorado and elsewhere, as long as states establish adequate regulations.

Goodlatte criticized the decision, saying it is tantamount to ignoring the law.

“The Justice Department’s decision not to enforce the Controlled Substances Act in states whose laws violate federal law is not a valid exercise of prosecutorial discretion, but a formal department-wide policy of selective non-enforcement of an Act of Congress,” Goodlatte said.

Holder countered that the DOJ was merely focusing on the most dangerous aspects of marijuana crime, such as trafficking or sales to minors.

“We don’t prosecute every violation of federal law,” he said. “We don’t have the capacity to do that and so what we try to do is make determinations about how we use our limited resources.”

Under Holder’s “Smart on Crime” initiative, the DOJ has altered the charging policies with regard to mandatory minimum sentences for certain nonviolent, low-level drug crimes.

Democrats on the panel lauded the move.

“In a country where nearly half of all federal inmates are serving time for drug offenses, the harshest [punishment] should be reserved for violent offenders,” said Rep. John Conyers (Mich.), the committee’s top Democrat.

But Goodlatte said judicial decisions meant to avoid triggering “mandatory minimum” sentences would put Holder at odds with the law.

“The attorney general’s directive, along with contradicting an act of Congress, puts his own front-line prosecutors in the unenviable position of either defying their boss or violating their oath of candor to the court,” he said.

Holder also faced questions from Republicans on the legality of the administration’s decision to delay the employer mandate in the Affordable Care Act.

In a terse back and forth with Holder, Rep. Steve Chabot (R-Ohio) argued that because an implementation date had been written specifically into the legislation, the executive branch had no authority to delay it.

“When Congress puts effective dates in laws, do we need to further state that the effective date cannot be waived or modified by the executive branch, or is the president required to follow the law, and also follow the dates set by Congress?” Chabot asked.

Holder responded that “the president has the duty, obviously, to follow the law,” but that “it would depend on the statute” and statutory interpretation of the law.

Holder also sought to deflect criticism over remarks he made during a speech to state attorneys general, which Chabot interpreted as suggesting they need not defend state laws defining marriage as between a man and a woman.

“You guys would never do that,” Chabot interrupted, with more than a hint of sarcasm.

Tensions also flared when Rep. Louis Gohmert (R-Texas) renewed a request for documents related to the Fast and Furious arms-trafficking operation.

“I realize that contempt is not a big deal to our Attorney General but it is important that we have proper oversight,” the Texas Republican said, referring to the House’s 2012 vote to hold Holder in contempt for withholding information about the botched operation.

Angered, the usually reserved Holder wagged a finger at Gohmert.

“You don’t want to go there, buddy, all right?,” he said.

“I don’t want to go there?” responded Gohmert. “About the contempt?”

“No. You should not assume that that is not a big deal to me,” Holder replied. “I think it was inappropriate, I think it was unjust, but never think that that was just a big deal to me. Don’t ever think that.”

– This story was updated at 8 p.m.

– Jonathan Easley contributed to this report.