WASHINGTON — A visibly irritated secretary of State battled with Republicans and Democrats alike at the Senate Foreign Relations Committee on Tuesday, at one point happily steering to the issue of climate change while one senator accused the administration of talking tough and wielding “a twig.”

John Kerry appeared before the committee to discuss the fiscal year 2015 budget request for international affairs but the lawmakers came out of the gate with concerns about Russia, Syria, Iran, and more — wrapped in warnings of a permissive foreign policy and crumbling credibility.

“I do think that from a bipartisan standpoint, people are very concerned right now about U.S. credibility, and Syria I think was the beginning of that,” ranking member Bob Corker (R-Tenn.) told Kerry. “I think there are concerns about Ukraine, our actual willingness to go forward and do something after we lost so much credibility around the red line issue, and so much credibility on the ground with just people in the neighborhood regarding not following through on commitments that were made. And I know that you know they were made.”

“…I will say to you that if things don’t change, you in effect could be presiding over a period of time where more U.S. credibility is lost than anyone could have imagined, and a time when the world is becoming less safe as a result,” Corker added.

Kerry insisted that his 29 years on the committee — he was chairman before moving into the Obama administration — gave him broad perspective on foreign policy.

“I’ve seen the ups and downs. I’ve seen the merry-go-round and the roller-coaster of American foreign policy up close and personal. And I will tell you that we’re living in a different time,” Kerry said.

“We’re living with a far more, almost 19th century, 18th century diplomatic playing field, where interests and, you know, some cases mercantilist interests, in other cases just security interests or territorial interests, other kinds of things are raising their head in ways that they didn’t during the Cold War, because they were suppressed,” he said.

Kerry’s successor at the helm of the panel, Chairman Robert Menendez (D-N.J.), lamented that the administration chose to slash the Western Hemisphere budget by 21 percent from fiscal year 2013.

“I don’t dispute the importance of other priorities laid out in the administration’s proposal, but I have seen year after year after year a continuous cut in the hemisphere,” Menendez said. “And I believe that those cuts lead us to lack a comprehensive approach to Latin America and the necessary resources to back it up.”

Menendez also panned a recent Wall Street Journal headline: “Obama Administration Shows Optimism on Iran Nuclear Talks.”

“I’m trying to glean where that’s from,” he said. “…With no sanctions regime in place, and understanding that every sanctions that we have pursued have needed at least a six-month lead time to become enforceable, and then a greater amount of time to actually enforce, that the only option left to the United States to this or any other president, and to the West, would be either to accept a nuclear-armed Iran or to have a military option.”

Kerry dismissed breakout as “just having one bomb’s worth, conceivably, of material, but without any necessary capacity to put it in anything, to deliver it, to have any mechanism to do so, and otherwise.”

He then admitted that “our goal” is not eliminating nuclear capability as much as “proving that this is a peaceful program.”

When Menendez told the secretary that the Russia was acting “in ways that are contrary to just about all of our interests,” Kerry replied that “the relationship with Russia produces both moments of consternation and conflict, as well as cooperation and effect.”

“This is not the bipolar, straightforward choice of the Cold War,” Kerry argued. “We’re living in an incredibly challenging time where some of the things that the East-West order took for granted most of my life, are suddenly finding a world in which American engagement is more critical.”

Corker said it’s difficult “to discern the good things that have occurred relative to our negotiations with Russia.”

“But, you know, when the president talked about his red line back in August of 2012, 30,000 Syrians were dead. Today, 150,000 Syrians are dead. We continue to talk about this shiny object, the chemicals. But people daily are being killed with barrel bombs,” the senator continued.

In a testy exchange with Corker, Kerry eventually agreed to share the administration’s Syria policy in a closed session with lawmakers “to the degree I am allowed to under the process and the law,” then proceeded to give a recounting of the timeline in the revolution and deterioration of the opposition.

“All of which everyone said was going to happen on the front end; very predicted,” Corker interjected. “Yes.”

“But what was the plan to not have that happen, Senator? I didn’t notice Congress racing to the barriers saying, ‘We’re going to, you know, we’re going to do something,'” Kerry sniped. “…And guess what, Senator? We came up with a better solution — to get all of [the chemical weapons] out by working through the diplomatic channel with Russia.”

Sen. Ben Cardin (D-Md.), noting that 10,000 children have already died in Syria, stressed, “I still don’t see a game plan to bring to justice those who have targeted innocent civilians for horrible outcomes, including the use of chemical weapons.”

“Couldn’t agree with you more, Senator, and all of those incidents are being chronicled and completely packaged, in a sense ready for that prosecution,” Kerry responded.

Sen. John McCain (R-Ariz.) told Kerry he was “about to hit the trifecta.”

“Geneva II was a total collapse as I predicted to you that it would be. The only tangible result is that people who went to Geneva for the Free Syrian National Council, their relatives were kidnapped,” he said of the administration’s attempts to hold talks between Bashar Assad’s regime and the opposition. “The Israeli-Palestinian talks, even though you may drag them out for a while, are finished. And I predict to you, even though we gave the Iranians the right to enrich, which is unbelievable, that those talks will collapse too.”

“…On the issue of Ukraine, my hero, Teddy Roosevelt, used to say talk softly, but carry a big stick. What you’re doing is talking strongly and carrying a very small stick — in fact, a twig.”

Kerry took issue with McCain’s “premature judgment about the failure of everything.”

“I guess it’s pretty easy to lob those judgments around, but particularly well before the verdict is in on any of them,” the secretary of State added. “…You know, the talks on Vietnam — you know this better than anybody — went on for how many years? Years. It took them a year to design the table to sit around.”

McCain reminded Kerry that “facts are stubborn things, as Ronald Reagan used to say: Geneva 1, there are 50,000 dead. Geneva II, there was 100 and some thousand dead in Syria. Now there’s 150,000 dead.”

“And your view of what the Ukrainians need is vastly different from what the Ukrainians think they need, which is a sovereign right to try to defend themselves, which is something that we have done historically, helping people who are struggling against overwhelming odds,” McCain added.

Kerry lit up with enthusiasm when his successor in the upper chamber, Sen. Ed Markey (D-Mass.), asked about progress on combatting climate change.

“We’re moving beyond them at a pace that shows us bringing more coal-fired power plants online, more methane being released, which is 20 times more potent than carbon, which is the consequence of the warming that’s already taking place,” he said.”…If the other guys are wrong, the people saying ‘don’t listen to it, what’s the worst that can happen?’ The worst that can happen is life as you know it on Earth is over.”

But even when the dais was mostly empty at the end of the hearing, Menendez and Corker weren’t letting Kerry go without parting words on the critical foreign policy issues being juggled by the White House.

“We have created an era of permissiveness; there’s no question. And I don’t think — I don’t see how you can debate that. I mean that scholars on both sides of the aisle understand that to be the fact, and facts are hard to overcome,” Corker said. “…The steps that we took in Syria have affected us in Iran. They’ve affected us in the peninsula. They’ve affected us in Ukraine. China is watching us. It’s affected us there.”

Kerry argued that the administration is getting a bad rap over the red line.

“On Syria, where we hear this notion that somehow there was a red line and then it wasn’t enforced, and somehow, you know, it’s a sign of weakness. I beg to differ. You know, facts are stubborn things,” Kerry said. “…The president made his decision and he was ready to use force, and we actually came up with a better solution, which is get all of the weapons out, all of them out, and that still leaves us with other options, folks.”