Pennsylvania U.S. Sen. Bob Casey is trying again on a bill to keep anyone who has committed a hate crime from buying guns.

Casey, a Democrat, first introduced the legislation one year ago, just days after the shooting at Pulse, a gay nightclub in Orlando, Florida. 

The measure would expand the categories of those banned from purchasing firearms to include anyone convicted of misdemeanor-level hate crimes — such as using a gun to threaten others based on their race, religion, sexual orientation, gender or disability. Federal law currently bans those convicted of felonies and domestic violence misdemeanors from buying guns.

Casey reintroduced the bill, known as the Disarm Hate Act, earlier this month as the country remembers the 49 victims of last year's Orlando shooting, as well as the nine people fatally shot during a prayer meeting at Emanuel AME Church in Charleston, South Carolina, in June 2015. 

"Hate unchecked usually grows in almost every instance," Casey said at a press conference Monday at Bethel AME Church in Ardmore, Montgomery County. "And hate unchecked with the use of a firearm can have a destructive impact."

However, it is unclear how the legislation might have prevented the Orlando or Charleston shootings; neither of perpetrator had been convicted of misdemeanor hate crimes before, according to news reports. And, with a Republican-dominated Congress averse to tightening gun laws, this bill is unlikely to go further than its predecessor, which never left the Senate Judiciary Committee.

But anti-gun violence advocates say it's part of a common-sense approach to limit sales of firearms only to law-abiding citizens and to keep them out of the hands of those with a record of harming others.

"We know people intent on harm will find ways to do harm. We make it too easy, though," said Shira Goodman, executive director of Ceasefire PA. "We don't have enough prohibited categories and, in some places, you can buy guns in private sales without any background check, regardless of whether you have a felony conviction."

While the future of this bill is uncertain, Tiara Parker wants lawmakers to go further in their attempts to curb gun violence. The 21-year-old Philadelphia resident survived the Pulse shooting with a gunshot wound to her left side. Her cousin Akyra Murray did not. 

Speaking from the pulpit of the church, Parker urged Casey "to dig a little deeper... to stop guns from being purchased so easily, starting from the sources, from where they come from.

"I will do what it takes to make sure that we start getting rid of them because I lost way too many people that are way too close to me because of a gun."

This is a corrected version of this story. A previous version incorrectly stated the names of the churches where the press conference was held and where the Charleston shooting occurred.