The US conducted the military action jointly with Britain and France in response to alleged chemical weapons use by the government of Syrian President Bashar al-Assad.
While the crisis in Syria was front and centre, Trudeau and Pence also expressed optimism about the state of NAFTA negotiations, the results of which will have dramatic ramifications for the US and Canada.
As for next steps for the summit, Pence said the US would be submitting a bid to host the ninth Summit of the Americas and repeated a familiar line about the Trump doctrine: "America First does not mean America alone". The conference brought together leaders of more than 30 countries.
Responding to a question, Pence said that the United States message to Russian Federation is: "You're on the wrong side of history".
Unlike past appearances at worldwide summits, the vice president had to dive into the packed agenda on short notice.
In meeting after meeting, Pence offered a low-key, extended hand.
The vice president also said that the topic of funding for Trump's proposed wall on the USA border with Mexico did not come up in Pence's meeting with Mexican President Enrique Pena Nieto.
Pence said they simply had a difference of opinion and some issues were "set aside, for a later date".
US Vice President Mike Pence has said he was "very hopeful" that a deal could be reached "within the next several weeks" in the renegotiation of the North America Free Trade Agreement (NAFTA) between Mexico, Canada and the US.
But US relations with Mexico had soured in recent weeks as US President Donald Trump has sought to link the trade talks to Mexican efforts to stop migrants illegally crossing the border into the US, and ordered National Guard troops to the border. Trump has long assailed the trade deal's impact on US workers and threatened to pull the USA out if he's unhappy with the terms. Maduro has been barred from the summit over his plans to hold a presidential election that the opposition is boycotting and that many foreign governments consider a sham.
Pence urged Maduro to accept humanitarian aid as the once-prosperous nation deals with humanitarian and economic crises.
The president believed Lerner, a longtime Republican strategist, was a card-carrying member of the "Never Trump" movement because he helped the conservative Club for Growth create ads as part of a multi-million dollar offensive against Trump during the GOP primaries.