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Christine Cotter, Associated Press
Vice President Joe Biden speaks at the Solar Power International Trade Show in Anaheim, Calif., Wednesday, Sept. 16, 2015. Taking aim at his potential political opponents, Biden railed against Republicans who "deny climate change" and want to shut down the federal government over funding for Planned Parenthood, and pleaded with them to "just get out of the way."

LOS ANGELES — In any other year, a pair of speeches by Vice President Joe Biden on transportation and sexual assault would raise few eyebrows in the political world. This isn't any other year.

Biden's visits Thursday to Michigan and Ohio are being closely watched for signs he's gauging his support in two battleground states that typically play a key role in electing the next president. As he considers making a late entrance into the 2016 presidential race, his usual vice presidential appearances have taken on the air of campaign stops, with supporters cheering "Run, Biden, Run" at nearly every stop.

The vice president himself is keenly aware that anything he says will be interpreted as tipping his hand to which way he's leaning. Addressing a U.S.-China summit in Los Angeles on Wednesday, he started praising a friend from the caucus kick-off state of Iowa before pausing to say he could no longer call him a "good friend."

"He lives in Iowa, and if I say anything, that means I'm doing something," Biden said with a wry smile.

Both of his stops on Thursday will call attention to issues that have long been central to Biden's identity as a political leader — and could play equally important roles in his message to voters should he choose to run for president.

In Detroit, Biden planned to join Mayor Mike Duggan at the city's transportation headquarters. As it works to pull itself out of an economic morass, Detroit has been pursuing major improvements in its bus system, including a shortage of buses and drivers that has made bus service unpredictable for those who rely on it. The Obama administration refused to bail out Detroit when it declared bankruptcy, but has helped its bus system in line with its call for improved U.S. infrastructure.

Biden will close his trip in Columbus at Ohio State University, which is announcing new steps on sexual violence prevention including mandatory awareness training for all freshmen next year. The school plans to dedicate a team to investigating allegations of sexual misconduct and to partner with a local sexual assault hotline.

It's a theme Biden has pressed for decades, and one resonating in this year's Democratic presidential primary. Earlier this week in Iowa, Hillary Rodham Clinton put forth her plan to try to end the scourge on campuses.

President Barack Obama won Ohio and Michigan in both 2008 and 2012.

The vice president has been deeply immersed in deliberations with his family and advisers about whether to enter the 2016 race. In recent days, Biden has opened a window into those deliberations, describing his lingering doubts about whether he has the emotional strength to mount a viable campaign just months after his son's death.

He's also started to speak out more directly against the Republican candidates he would face if he won the nomination. After denouncing front-runner Donald Trump on Tuesday for promoting a "sick" anti-immigrant message, Biden traveled Wednesday to Anaheim, California, where he mocked Republicans who question mainstream science on global warming.

"I think if you pushed them, they'd probably deny gravity as well," he said.

Associated Press writers Julie Carr Smyth and Andrew Welsh-Huggins in Columbus, Ohio, contributed to this report.

Reach Josh Lederman on Twitter at http://twitter.com/joshledermanAP