Some of America's key security allies are hopeful that President-elect Trump's impetuous streak might spur resolution to drawn-out conflicts in Ukraine and the Middle East, but there's also deep anxiety about the “America First” agenda, compounded this week by Trump's tariff threats.   These competing sentiments were on display over the weekend at the Halifax International Security Forum, where top diplomats, defense ministers, U.S. lawmakers, foreign politicians, military brass, and democracy activists scoured for any clues on where Trump can be convinced to stand with allies, and where he is intent on going rogue. Rosa Brooks, a law professor at Georgetown who helped lead a series of spring 2024 simulation exercises examining how a second Trump administration might play out — with “sobering” results — said she was dismayed to see so many people at the conference assume a second Trump administration will be “business as usual.” “Nothing about his postelection statements suggests this will be business as usual. Both in the U.S. and in allied countries, people should be expecting Trump to follow through on his threats, and should brace for the political and economic instability his actions will cause,” she said. “I don’t want to put too fine a point on it, but the future of the world is at stake,” said a former official of a NATO country and high-level participant at the conference. “And if the United States goes bad then we’re done. We’re going to enter a century of a period of darkness.”  In security and defense circles, anxiety about the incoming administration has been compounded by surprise picks like Tulsi Gabbard for chief of intelligence, Pete Hegseth for the Pentagon and Elon Musk as a close adviser on global affairs.  Sen. James E. Risch (R-Idaho), the incoming chair of the Senate Foreign Relations Committee, sought to play down those worries.  “I wouldn’t focus on one person,” he said, when asked about the risk Gabbard poses to analyzing and presenting the threat picture to Trump, when she has been criticized for echoing Russian propaganda.  “I am not concerned that a person is going to influence the president to the point where he changes his basic view on things.”  While Trump has said Ukraine's survival is important to the U.S., he has refused to commit to backing Ukraine’s victory against Russia, a shared goal of those assembled in Halifax. Yet the president-elect’s focus on dealmaking, and even his perceived impulsiveness, is being welcomed by some Ukraine supporters, tired from President Biden’s drawn out decisionmaking on sending weapons systems and allowing Ukraine to use them for strikes into Russia.  “We need brave and just decisions, I will not hesitate to say historic decisions,” Ruslan Stefanchuk, speaker of Ukraine’s Parliament, said in a speech to the conference.  “It is exactly such decisions that must be timely made – in Halifax, Ottawa, Washington, Brussels, Paris, Berlin and London.” Batu Kutelia, the former ambassador to the U.S. from Georgia, who also served as a senior defense official in the country, said there’s a shared sense that the current approach isn’t working.  “Some kind of a cautious optimism, and also the change – that something which is not working for more than 1,000 days for Ukraine, so something needs to be changed,” he said. Peter Van Praagh, founding president of the Halifax International Security Forum, said the optimism does not change the difficult reality, with Russian forces deeply entrenched across eastern Ukraine.  “I don’t think there’s any new understanding that the difficulties are any less challenging than they were yesterday,” he said.   “If you take a hard look at this stuff, yes the solutions are challenging, but there are solutions.”  Allies are also bracing for a trade war, as Trump has made tariffs a central piece of his economic and foreign policy agenda.  Risch sought to reassure Canada that Trump would not impose his threatened, global 10 percent tariff, giving an emphatic “no” when asked about the prospect Saturday. That message was undercut Monday when the president-elect called for a 25 percent tariff on Canada and Mexico (and additional 10 percent tariff on China) to pressure a crackdown on drug trafficking and illegal immigration.   Canada Minister of National Defense Bill Blair told The Hill that drastic trade measures would have “implications,” adding “it's to the mutual benefit of both countries to make sure we’re able to work together and for our industries to support each other and collaborate.” Blair has tried to get ahead of Trump’s criticism over Canada’s relatively low defense spending, but he said a trade war could disrupt Canada’s efforts to ramp up cross-border military production contracts.   The European Union has reportedly started preparations on retaliatory taxes on American imports.  “It doesn't make sense to reveal secrets or to tell you exactly how we prepare, but what I can tell you is that the European Commission is prepared if there should be a disagreement on tariffs,” Tobias Lindner, state minister in Germany’s foreign ministry and transatlantic coordinator for the incoming Trump administration, told reporters.  “We believe to negotiate, to speak, to talk, is the best way to get through this. And we both are economically benefiting from our ties.”  And Trump’s controversial nominee Hegseth for secretary of Defense stirred pushback at the conference, particularly over his recent remarks saying women should not serve in combat roles.  Canada’s chief of the armed forces, Gen. Jennie Carignan, said women in combat roles are “not some kind of social experiment.” “I wouldn’t want anyone to leave this forum with this idea that women are a distraction to defense or national security,” Carignan said.  Sen. Jeanne Shaheen (D-N.H.), the incoming ranking member of the Senate Foreign Relations Committee, said at the forum that “hopefully there will be a background check” amid sexual assault allegations against Hegseth.   “I don't think having somebody who has a questionable record on that issue is a message to the women of the military that we want to send,” she said.  And Musk’s unpredictability was also touched on, with Norway’s Foreign Minister Espen Barth Eide pointing to Oslo’s reliance on Starlink satellites in remote parts of the Arctic “as long as Elon Musk is happy, I guess.” Musk reportedly joined a phone call between Trump and Ukrainian President Volodymyr Zelensky after the election and met with Iran’s ambassador to the United Nations earlier this month.  Trump has assembled a vehemently pro-Israel team of advisers and has promised to take a hard line against Iran for fueling terrorism throughout the region, posing a threat to U.S. forces and regional allies.  “The new administration makes the Islamic Republic [of Iran] nervous,” said Masih Alinejad, an Iranian journalist and activist who is under persistent threat of assassination from Tehran. “I still believe that we have to push the new administration to stick with their own promises to support the Iranian people rather than going back to the negotiation table, that’s my hope.” The overwhelming focus of the conference was rallying ongoing international support for Ukraine and appealing to Republican members of Congress, in particular, to hold firm in their positions backing Kyiv, despite skepticism from Trump and far-right factions in Congress.  “Senator, when you have conversations with your colleagues, what is the argument that is the most successful to talk about the support to Ukraine,” Canadian Foreign Minister Mélanie Joly asked Sen. Mike Rounds (R-S.D.), an outspoken Ukraine supporter.  “Because clearly your argument of ‘we need to fight now because if not it will be even more costly to us in terms of lives and in terms of money’ is a good one, and this is one that we've been all using.” There was even an appeal by Taiwan’s former President Tsai Ing-Wen, pushing back on arguments that the U.S. should be focusing its foreign military support on Taiwan, given the threat from China.  “We still have time,” she said in conversation with PBS’s Nick Schifrin. “The U.S. may have this issue of whether they have enough stock — but my thought is that they should do whatever they can to help the Ukrainians, we still have time to prepare for ourselves with the rest of the world.”