Former Sen. Rick Santorum (R-Pa.) is announcing today that he's taking another stab at running for president. In 2012, Santorum made a strong showing, finishing second in the Republican primary behind Mitt Romney. On Wednesday, he'll rev up the campaign engine once again with a speech in his hometown of Cabot, Penn. The former senator -- known for his vocal social conservatism and appeal to the working class -- is entering a crowded Republican field (he is seventh to enter the race).

Here's where he stands on five issues important to Millennials.

1. College costs and student debt.

Santorum's higher education message has changed over time. In 2006, Rick Santorum was in favor of every Pennsylvanian having access to higher education, as pointed out by Talking Points Memo. According to an Archive.org copy of his 2006 Senate campaign site, this was Santorum's higher education stance:

"In addition to Rick's support of ensuring that primary and secondary schools in Pennsylvania are equipped for success, he is equally committed to ensuring the every Pennsylvanian has access to higher education. Rick Santorum has supported legislative solutions that provide loans, grants, and tax incentives to make higher education more accessible and affordable.

"Rick Santorum supports increased funding for Pell Grants, and since 2001 funding for the Pell Grant program has increased by 47 percent. Pennsylvania students have benefited tremendously from Pell Grants; providing a college education for our state's youth who otherwise might not be able to afford one."

Six years later while running for president, however, Santorum, who has a BA, MBA, and JD, called President Obama a "snob" for wanting to make higher education accessible to all.

"President Obama wants everybody in America to go to college," Santorum said in an appeal to the working class at his Michigan campaign stop. "What a snob!"

Back in 2012, Inside Higher Ed wrote an in-depth piece about Santorum's apparent shift in beliefs:

During Santorum’s years in the House and Senate, he also advocated for the federal government’s role in supporting colleges and universities financially in terms that would now be anathema to his campaign.

“I believe that there needs to be an active federal role in higher education because institutions of higher learning constitute a nationwide educational infrastructure,” Santorum wrote on his Senate website, according to a version archived in 2001. “Clearly, higher education is a national concern to be addressed, in part, on a national basis.”

During his time in office, Santorum was generally supportive of private colleges and universities and federal student aid, Mary Young, vice president for government relations at the Association of Independent Colleges and Universities of Pennsylvania, wrote in an e-mail to Inside Higher Ed.

Despite that stated policy position, "Santorum voted NO on an amendment [in 2006] to the yearly budget resolution that would have increased funding for higher education, including programs for vocational training and adult education," according to The Huffington Post. This same amendment would have helped with student loan forgiveness for math and science teachers and would have upped the maximum amount of Pell Grants.

Santorum is also known for supporting for-profit colleges, which have recently gained a reputation for high tuition that leaves their students in debt. At a 2012 Detroit campaign event, he slammed President Obama for cracking down on for-profit colleges.

"[Obama] believes that private-sector schools are somehow evil and they're abusive, and his Education Department has done everything they could to make it harder for them to compete for loans and other things and to stay in business," Santorum said.

During his time in the Senate (which ended with a failed re-election bid in 2006), Santorum was also known for regularly attending the annual forum of historically black colleges and universities.

2. Marijuana.

Santorum's stance on marijuana is unclear. This is best demonstrated by a series of videos from 2012 where he straddled the line, both calling for the federal government to enforce drug laws while also invoking states' rights to implement their own laws.

At a 2012 campaign stop in New Hampshire, a woman asked whether she should be arrested for using marijuana. "Depends what the laws in your states are," Santorum responded. Here is the video:

At a later campaign stop, Santorum was asked by the same woman to clarify his stance about marijuana and whether states should have the right to regulate it. He said that state laws are the most important drug laws, but also that the federal government "has a role in making sure that those drugs are not in this country and not available and that people who use them illegally are held accountable."

He was asked about medical marijuana and states' rights back in 2012 and stated that he didn't know his medical marijuana laws that well:

In terms of his own drug use, Santorum admitted in 2011 that he smoked marijuana in college:

3. Immigration.

Santorum takes a hard line on immigration. In a January 2015 speech, he stated that immigrants are taking American jobs.

"Since 2000, there have been 6 million net new jobs created in America," Santorum said, citing a June 2014 study from the Center for Immigration Studies.

"How many of those net new jobs are held by people who were not born in this country?" he continued. "All of them."

However, as FactCheck.org points out, Santorum was incorrect in that statement:

"Rick Santorum touted a shocking statistic to Iowa voters: Of the '6 million net new jobs created in America' since 2000, 'all of them”'are held by immigrants. That’s not accurate. Santorum ignores the 2.6 million job gains by native-born Americans over the age of 65 in the same time period."

Santorum has frequently discussed his problem with undocumented immigrants breaking the law by entering the country illegally, and he believes in beefing up border security and finishing a fence on the Mexican-American border (which he voted for in the Senate in 2006).

In a 2011 debate, Santorum spoke out against giving in-state tuition rates to undocumented students and also stated that English should be the official language:

"I'm the son of an Italian immigrant. I believe in immigration, as an important part of the lifeblood of this country. But what we have is a problem of an unsecure border. Unlike Gov. Perry, I believe we need to build more fence. I believe that we need to secure the border using technology and more personnel. And until we build that border, we should neither have storm troopers come in and throw people out of the country nor should we provide amnesty."

...

"What Gov. Perry's done is he provided in-state tuition for illegal immigrants. Maybe that was an attempt to attract the illegal vote--I mean, the Latino voters. But you attract Latino voters by talking about the importance of immigration. You talk about the importance of having English as the official language of this country."

During his time in the Senate, he voted against a pathway to citizenship for guest workers. He also voted to limit welfare for legal immigrants and against providing Social Security to undocumented immigrants.

4. Environment

At a 2012 campaign event in Colorado Springs, Colo., Santorum called global warming a "hoax." He also slammed other candidates for supporting cap and trade, a proposed law to limit carbon emissions. According to Politico, Santorum said supporters of cap and trade "bought into the science of man-made global warming, and they bought into the remedy, both of which are bogus."

"I believe the earth gets warmer and I also believe the earth gets cooler," Santorum told Rush Limbaugh in 2011. "And I think history points out that it does that and that the idea that man, through the production of CO2 — which is a trace gas in the atmosphere, and the man-made part of that trace gas is itself a trace gas — is somehow responsible for climate change is, I think, just patently absurd when you consider all the other factors, El Niño, La Niña, sunspots, moisture in the air. There's a variety of factors that contribute to the Earth warming and cooling."

5. LGBT rights

Rick Santorum has spoken out against gay rights. In fact, there are sites that track his most offensive anti-gay comments. Writer and LGBT activist Dan Savage famously led a campaign to define 'santorum' as a reference to anal sex. For a period of time, Savage's efforts propelled the definition to the number one Google search result for "santorum."

Unsurprisingly, he is against gay marriage. Most recently, he has stated that he would not attend a gay wedding, if invited:

In a 2014 statement to Townhall.com, he predicted that gay marriage would lead to fewer heterosexual marriages.

“When we have less of this in America, when you have less of that in society at all, then society struggles and suffers," Santorum continued. "Economically, it suffers. It’s important for us to stand up for what is best for children, what’s best for society, what’s best for the economy, and make that case."

Santorum also spoke out against allowing gay people into the Boy Scouts of America.