Lindsey Graham
U.S. Republican presidential candidate U.S. Senator Lindsey Graham talks with supporters after announcing his campaign for the 2016 Republican presidential nomination in Central, South Carolina June 1, 2015.REUTERS/Christopher Aluka Berry

It's hard to keep count, but yet another Republican candidate has entered the 2016 presidential race. South Carolina Senator Linsey Graham became the ninth GOP candidate when he announced his presidential bid on 1 June.

Graham, who is the fourth senator to run for the Republican nomination, made his announcement in his hometown of Central, South Carolina, according to Voice of America. The 59-year-old told supporters he wants to reach the White House "to defeat the enemies that are trying to kill us" and affirmed that the US "will never enjoy peaceful co-existence with radical Islam".

But what makes Graham different from the other declared GOP candidates and the others to come? IBTimes UK breaks it down to three things you should know about the newest conservative contender.

Supports US intervention abroad

The former US Air Force lawyer is an outspoken critic of President Barack Obama's approach to US foreign affairs. According to NBC News, Graham has also criticised fellow Republican candidate Kentucky Senator Rand Paul, who blames US intervention abroad for the rise of Islamic State (Isis).

"Those who believe we can disengage from the world at large and be safe by leading from behind, vote for someone else. I am not your man," he said.

While Graham has poll low compared to other Republicans, a recent NBC News/Wall Street Journal survey in May revealed Republicans voters name national security as the number one priority for the federal government. Graham's focus on national security, therefore, should earn him some support.

Fierce champion of immigration reform

As previously reported by IBTimes UK, Graham is a firm supporter of immigration reform and believes far-right conservatives in his party could scare away potential Latino voters.

"I worry that we'll marginalise ourselves once again with the fastest growing community in America, the Hispanic community," he said. Graham, who is a long-time ally of another immigration reform advocate Arizona Senator John McCain, told NPR he wants real debate on immigration reform during the GOP primaries.

According to NBC News, Graham has spent more time than any other 2016 presidential candidate working on a federal immigration policy. In 2013, he worked alongside fellow presidential candidate Florida Senator Marco Rubio on the failed "Gang of Eigh" immigration reform bill.

Mixed record on climate change

Huffington Post has reported that Graham is one of the few Republicans who has acknowledged climate change. The three-term senator and fellow candidate George Pataki are the only contenders to be "pro-actively engaged on climate," according to HuffPost.

Graham joined Democrat John Kerry and independent Joe Lieberman in 2009 and 2010 to work on legislation that would have established a cap-and-trade system to rein in greenhouse gas emissions.

"I have come to conclude that greenhouse gases and carbon pollution is not a good thing," he said in 2010. "Whatever political push back I get, I'm willing to accept because I know what I'm trying to do makes sense to me. ...I am convinced that reason, logic and good business sense, and good environmental policy, will trump the status quo."

However, just weeks after walking away from the bill, Graham changed his tune, denying man-made emissions were to blame for global climate change. He also stated he would vote against the legislation he helped create, according to HuffPost.

In March, he reverted back to his initial position.