President Obama went through with a campaign appearance in Las Vegas on Wednesday evening and, after laboring to quiet an exuberant crowd, began his speech with a somber tribute to the four Americans killed Tuesday in Libya.

Obama, visibly weary and seeming to struggle to display the usual energy and sharpness of his campaign appearances, opened with a description of the “tough day that we’ve had today.” With a crowd of more than 8,000 at a Las Vegas convention center still screaming and cheering, Obama, wearing no jacket and his sleeves rolled up, held up his hands and paid tribute to the dead, who he said “were working to advance the interests and the values that we hold dear as Americans.”

“It’s a reminder that the freedoms we enjoy, sometimes even the freedoms we take for granted, they’re only sustained because there are people like those who were killed who are willing to stand up for those freedoms, who were willing to fight for those freedoms, in some cases to lay down their lives for those freedoms,” the president said. “So tonight, let’s think of them and thank them.”

Obama also reiterated his promise to “bring their killers to justice.”

He made no mention of his Republican challenger Mitt Romney, who came under fire Wednesday after sharply rebuking the Obama administration’s response to the violent attacks on both the U.S. Consulate in Benghazi and the U.S. Embassy in Cairo.

After briefly referencing the events in the Middle East, Obama quickly pivoted to his usual stump speech, laying out the choice he says Americans face in this election. On the one hand is the option of going backward, he said, to less regulation of Wall Street, lower taxes for the wealthy and what he described as a failed belief that success at the top trickles down to the middle class. He then outlined his own vision — to go “forward” and continue investing in education and infrastructure, and implementing policies to help businesses grow, hire more workers and sell their products around the world.

In one riff on the Republicans, Obama said: “You may not have watched their convention, but if you didn’t, let me summarize. What they said is, ‘We want to give you more tax cuts, especially tilted toward the wealthy, and everything will be okay.’ And this is their prescription for everything. Tax cuts in good times. Tax cuts in bad times. Tax cuts when we’re at peace. Tax cuts when we’re at war. Tax cuts to lose those few extra pounds. Tax cuts to give your love life that extra kick.”

Obama also ran through the usual policy points: His promise to help homeowners dig out from underwater mortgages, preserve student-loan funding, preserve tax cuts for the middle class, protect Medicare from being transformed into a voucher program. He also touted his list of accomplishments: ending the war in Iraq, starting the wind-down of war in Afghanistan, bailing out the auto industry.

And, in a nod to the importance of Latino voters, particularly in Nevada, Obama chose a young woman from Mexico, Adriana Ortiz, who became a U.S. citizen in 2008, to introduce him.

Obama’s visit to Nevada was his 14th since he took office and his seventh this year, a reflection of the state’s status as a battleground that could determine the outcome of the election.

He was scheduled to travel to Denver after his Las Vegas appearance for a campaign event in suburban Golden on Thursday morning.