During her speech Tuesday to a joint session of the United States Congress , Chancellor Angela Merkel found herself right in the middle of American domestic politics.

At first glance, everything in the scene resembled a normal state visit. Angela Merkel, dressed in a simple black outfit, stood at the rostrum. Behind her sat Vice-President Joe Biden and the speaker of the House of Representatives, Nancy Pelosi. Merkel had just spoken of the "partnership in leadership" between America and Germany and her appreciation for the American people . A delegation of around 30 Congress members had earlier escorted her into the House chamber. A master of ceremonies had announced her entry, which was accompanied by loud applause and even shouts of approval from some members.

But then her attention turned to climate change. "We need the readiness of all nations to assume internationally binding obligations," Merkel said in a serious tone. "We cannot afford failure with regard to achieving the climate protection objectives scientists tell us are crucial." She went on: "That would not only be irresponsible from an ecological point of view, but would also be technologically short-sighted, for the development of new technologies in the energy sector offers major opportunities for growth and jobs in the future."

As Merkel spoke these words, the Democratic Senator Chris Dodd nudged his colleague Barbara Boxer, a known supporter of action on climate change from California, as if signaling her to pay attention. But she was already applauding enthusiastically. Then she got to her feet and pointed with her arm to the seats to the right of Dodd, where his Republican colleagues were sitting. Listen closely, she seemed to be saying.

Bogged Down

A draft, tougher climate change bill is currently bogged down in Congress. The House of Representatives has passed it, but the Senate is blocking it -- because the Republicans are putting up resistance, as are some Democrats from states which are home to heavily polluting industries. Under these circumstances, the chances of progress being made at the UN climate change summit in Copenhagen in December appear to be virtually zero.

Merkel's visit was intended to send a signal. President Barack Obama also made that clear earlier on Tuesday during their meeting in the Oval Office, when he called Merkel "an extraordinary leader  on the issue of climate change."

After Merkel made her climate change comments during her speech to Congress, more and more Democrats got to their feet and applauded. It went on so long that even Obama's National Security Adviser James Jones got up from his chair right at the front and clapped.

It was a domestic political message backed up by foreign support. Just how urgent it is was shown by the reaction of the Republicans, when Merkel in the following sentence expressed her optimism that even China and India will be prepared to make concessions on climate change. An audible growl of incredulity arose from the deputies around John Boehner, the Republican minority leader in the House of Representatives, as the chancellor spoke.

That moment made clear just which issues will be important to the -- at times rather vague -- "trans-Atlantic partnership" in the future.

Europe's Waning Importance

In that respect, Merkel made a strong appeal to her audience. "I am deeply convinced that there is no better partner for Europe than America and no better partner for America than Europe," she told the joint session of Congress. But the applause which the sentence was clearly intended to generate was somewhat dutiful. The relationship with Europe is rarely on the agenda in Washington at the moment. The future co-operation with Asia, especially China, is much more urgent. Obama is heading there next week for a long state visit. Just how important the Americans regard Europe at the moment could be seen in the fact that the only prominent member of the US cabinet to attend Merkel's speech was the national security adviser, James Jones.

America's supposedly close relationship to Europe is based mainly on memories. Merkel was able to contribute a few authentic recollections from her own biography. She paid tribute to German reunification, something to which President George Bush Sr. had significantly contributed, she said. "Twenty years have passed since we were given this incredible gift of freedom," the chancellor said. "But there is still nothing that inspires me more, nothing that spurns me on more, nothing that fills me more with positive feelings than the power of freedom."

She talked about the American pilots who took part in the Berlin Airlift, the US soldiers who were stationed in Berlin and the visits by Presidents John F. Kennedy and Ronald Reagan to the divided city. "I know, we Germans know, how much we owe to you, our American friends. We as a nation, and I personally, will never forget that."

Of course, as a speaker, Merkel is no Obama -- even when she has such powerful material to draw on. (Her speechwriters are clearly also not as good as the US president's; Kennedy's "1961 visit" to Berlin, during which he made his famous "Ich bin ein Berliner" speech, actually took place in 1963.) Merkel's enthusiasm for American jeans during her youth in communist East Germany is the kind of thing that any American politician would make into a moving story. However the German chancellor managed to make it sound mundane, merely talking about "a certain brand of jeans that were not available in the GDR and which my aunt in West Germany regularly sent to me."

But even this passage earned the chancellor friendly laughter. At the very end of her approximately 35-minute-long speech,  Merkel switched into English to talk about Schöneberg City Hall in Berlin, where a replica of the American Liberty Bell has hung since 1950. Merkel delivered the sentences with an impeccable pronunciation and the Congress members applauded wildly.

A Strong Ally?

It was, without a doubt, a good day for the chancellor. But what does her speech mean for the future of German-American relations?

Ahead of his meeting with Merkel at the White House, Obama had praised Germany as an "extraordinarily strong ally." But strong in what sense? In the West's approach to dealing with Iran's suspected nuclear weapons program? On that issue, Merkel had clear words for her audience in the Congress. "A nuclear bomb in the hands of an Iranian president who denies the Holocaust, threatens Israel and denies Israel the right to exist, is not acceptable," she said, to much applause.

Is Germany a strong ally when it comes to American policy on Afghanistan? Or is it mainly an ally to Obama on the issue of climate change? Do Europeans need to formulate their own goals more clearly and act more confidently towards America, as researchers at the European Council on Foreign Relations recently recommended ? Or will President Obama make clearer demands to Merkel, now that she has been re-elected as chancellor?

The president does not simply make demands, Merkel says in regard to Obama. Rather, he tries to persuade his partners to go to their own limits in terms of what they are prepared to do. Sources close to Merkel say that the German chancellor wanted to emphasize in her speech that relations between the Americans and the Germans need to be constantly renewed.