WASHINGTON (AP) — Just as Congress is hitting something of a bipartisan stride on such issues as Medicare, Iran and trade, President Barack Obama and his White House team have decided to go after their Republican critics, picking fights and scornfully calling them out by name.

In just the past week, the president and his spokesman have targeted Senate Majority Leader Mitch McConnell and Republican Sens. John McCain and Charles Grassley, on topics from climate change to the Iran nuclear deal. On Friday, he used a news conference to deliver to senators a testy lecture about the delayed confirmation of attorney general nominee Loretta Lynch.

This is a White House unleashed, forgoing niceties for the kind of blunt talk some of Obama's allies have been demanding for some time. But the rhetoric carries risks of sounding peevish and signals that a president who once ran on the promise of changing the tone in Washington has fully embraced its political combat.

Obama on Friday decried the long wait Lynch has faced since she was nominated in early November.

"Enough. Enough!" he said, addressing Senate Republicans. "This is embarrassing, a process like this."

Last Saturday, Obama hit McCain especially hard, after his 2008 presidential rival declared a major setback in the Iran nuclear talks after Iran's supreme leader, the Ayatollah Ali Khamenei, demanded that sanctions against Tehran had to be lifted immediately after a deal went into place. (The preliminary deal says the sanctions will be lifted as Iran proves it is complying with limits on its nuclear program.)

Obama cast McCain's criticism as an assault on the credibility of Secretary of State John Kerry.

"That's an indication of the degree to which partisanship has crossed all boundaries," Obama said. "That's a problem. It needs to stop."

He went on: "We have Mitch McConnell trying to tell the world, oh, don't have confidence in the U.S. government's abilities to fulfill any climate change pledge that we might make."

On Thursday, White House spokesman Josh Earnest singled out Grassley, declaring comments he made about the Lynch vote "duplicitous."

Asked how harsh words might help his cause, Earnest replied: "Being nice has gotten us a 160-day delay. So maybe after they look up 'duplicitous' in the dictionary we'll get a different result."

It was the kind of "ouch" moment seldom heard from the White House.

Pat Griffin, who was legislative director in the Clinton administration, said the tone from the White House dovetails with the aggressive strategy Obama has set since his party lost control of the Senate in November and put Congress in Republican hands.

"I think the president since the election has kept these guys on their heels," Griffin said. Obama and his aides "have come to understand that you don't get the attention of these guys and the attention of the country without having some edge."

Republicans maintain Obama would be better off working on bipartisan efforts, such as trade. Top lawmakers on Thursday revealed a bipartisan agreement to give Obama authority to negotiate trade deals without having to face delays in Congress. But many Democrats oppose such deals, fearing they will cost jobs or lower environmental standards.

"Rather than spending so much time criticizing people like Chuck Grassley and myself, he ought to be out there lining up the Democratic votes for trade promotion authority," McConnell said in an interview Friday. "This is a time for presidential leadership."

On the White House needling, "We're used it," said McConnell, who frequently jousts with Senate Minority Leader Harry Reid. "We used to get it from the Democratic leader routinely."

As for Lynch, McConnell said, "The cheap shots at Sen. Grassley were particularly inappropriate."

Lynch's confirmation has been delayed because McConnell has wanted to pass a sexual trafficking bill through the Senate first. That bill has been held up because of Democratic objections to anti-abortion language in the bill. McConnell predicted the dispute would be resolved next week, opening the way for a vote on Lynch.

For many Democratic allies of the White House, Obama's confrontational talk could have even come sooner.

"If you're sitting at the White House looking at Republicans on Capitol Hill, especially on the House side, you can't expect either much respect from them or a willingness to get much done," said Jim Manley, a Democratic strategist and former top aide to Reid. "Point two, as we move into the primary season, the base is looking for a more combative tone from the White House as well."

The last two years of a second term are especially liberating for presidents. They don't face re-election and they don't feel they have much to lose legislatively by going on the offensive.

"It feels good to do that when you have been bottled up," said Matt Bennett, a veteran of the Clinton White House.

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