Why won't President Obama act to stop the slaughter of Christians in the Middle East by ISIS? 

We heard a lot of discussion and criticism this week on Fox News about this topic. 

In her "Off the Record" commentary, Greta Van Susteren took President Obama to task for failing to act forcefully against the atrocities. 

Her strong words came just after the release of another gruesome video by ISIS, purporting to show the beheadings of a group of Ethiopian Christians in Libya.

Van Susteren said despite video proof of the atrocities as they happen, some want to "bury their head in the sand."

She called on President Obama to step forward and lead the "great nations" of the world in a fight to stop the killings.

But she said if President Obama will not act, maybe German Chancellor Angela Merkel or British Prime Minister David Cameron will. 

"I don't care who takes the lead. I just know what's right. My generation just can't continue to look the other way," she said.

Watch her commentary below.

On "The O'Reilly Factor," Fox News contributor Kirsten Powers followed up on her criticism of the president for being "largely silent" on the continuing murders.

She brought up the reports of 12 Christian men being thrown off a migrant boat after a group of Muslims saw them praying. 

The boat was full of refugees and heading from Libya to Italy.

But Powers noted that when the murders were brought up to the Italian Prime Minister Matteo Renzi at a joint press conference at the White House, President Obama declined to make a comment.

"As Renzi was questioned about the incident, Obama was mute on the killings. He failed to interject any sense of outrage or even tepid concern for the targeting of Christians for their faith. If a Christian mob on a ship bound for Italy threw 12 Muslims to their death for praying to Allah, does anyone think the president would have been so disinterested?" Powers wrote in her USA Today column.

She explained to O'Reilly that she believes the persecution of Christians in the Middle East and North Africa is reaching a "critical tipping point."

O'Reilly asked whether we should really expect President Obama to admit he was wrong.

Powers said she thinks the president should acknowledge that there's a "religious cleansing" going on, without bringing up the Crusades or trying to point out instances where Muslims have been persecuted.

Watch the discussion below.