The future of a well-known think tank, the David Horowitz Freedom Center, is threatened by a Southern Poverty Law Center-driven move by credit card giants Mastercard and Visa to stop processing donations to the non-profit, its supporters say.

"This is getting very serious. It won't stop with David Horowitz or me. The Left is moving quickly to silence all dissenting voices in the run-up to the 2018 elections," said Robert Spencer, whose influential Jihad Watch site is hosted by Horowitz's organization.

Spencer, also a target of SPLC, recently was banned from the web-based funding site Patreon, which claimed Mastercard demanded the move.

Both Mastercard and Visa declined Thursday to respond to multiple WND messages requesting comment.

TRENDING: 3 ways Red China is helping elect Joe Biden

Spencer believes Mastercard is targeting "accounts that have been smeared by the hard-Left propaganda hate group the Southern Poverty Law Center."

As WND has reported, many companies and organizations, including Amazon.com, have relied on the far-left SPLC's "hate list" to determine whether or not they will do business with a particular person or organization. While the "hate list" features radical movements such as the Ku Klux Klan, in recent years it has included organizations that promote traditional marriage, such as the Alliance Defending Freedom and the Family Research Council.

Last week, Spencer revealed he had been "axed from Patreon, without explanation, warning or notice -- no doubt as part of the ongoing efforts of the Left to deny all platforms to those who reject its agenda."

Long before any other news organization, WND was exposing the coordinated campaign by the “Internet Cartel” – Google, Facebook, YouTube, Twitter, Amazon, Apple and others – to silence free speech by censoring and suppressing independent, conservative and Christian expression on the Internet. Here are highlights of WND’s groundbreaking news and analysis of what has been called the 21st century's greatest assault on America’s fundamental freedoms of speech, press and religion.

The David Horowitz Freedom Center, founded in 1988, documents left-wing attacks on America and its constitutional system.

It has charged that the left is "willing to collaborate with America's enemies abroad and criminals at home to bring America down."

The Gateway Pundit posted a message from the center stating it was "under attack" by SPLC.

"For years, the SPLC has labeled the Freedom Center a hate group and tried to get organizations like Amazon, Facebook and Twitter to ban us and silence our message. Yesterday, SPLC finally convicted Mastercard and Visa to cut us off. Now we can't process donations from any major credit card companies.

"This blow could be the end of the Freedom Center. Decades of work, down the drain because the hateful Left wants to squash free speech and silence an organization that dares to question them."

Spencer said: "The freedom of speech is the foundation of a free society, and it is rapidly being destroyed in the United States. Not only are Horowitz, and me, and Alex Jones, and Dennis Prager, and Gavin McInnes being silenced – with this credit card action they're trying to make sure that we cannot make a living, and will be quite literally destroyed, personally as well as professionally.

"And there will be more victims," he warned. "This totalitarian action needs to be stopped quickly, or it will destroy all who are not doctrinaire Leftists."

Jim Hoft at Gateway Pundit commented: "No conservative voices will be allowed in America. The left is out for complete elimination of prominent conservative voices and publishers."

WND reported in August 2017 the digital payment platform PayPal restricted Spencer's Jihad Watch and his American Freedom Defense Initiative from receiving donations.

As WND recently reported, Facebook, YouTube and Apple banned Alex Jones and Infowars within hours of each other.

And WND reported last month moderate Muslims and counter-terrorist activists are increasingly being restricted by Silicon Valley, while terrorist content remains on social-media platforms, according to researchers.

However, the leaders of Christian organizations that the SPLC falsely labels as "hate" organizations have planned a massive legal response that could include as many as 60 separate lawsuits.

"What we're considering is not a class-action lawsuit," Mat Staver, founder and chairman of Liberty Counsel, a Christian nonprofit branded a "hate group" by SPLC and currently suing the charity navigation site GuideStar, told PJ Media. "These are individual lawsuits that we're looking at, not class action."

He explained that the roughly 60 organizations considering the lawsuits intend to "make the SPLC defend itself all over the country."

SPLC, while condemning groups for "hate" for supporting biblical sexuality and marriage standards, has been linked to two shooting attacks.

In 2012, Floyd Corkins chose the headquarters of the Family Research Council as a target based on SPLC's labeling of it as a "hate group." And last year, James Hodgkinson, inspired by SPLC, opened fire on Republican lawmakers as they practiced for the annual congressional baseball game, severely wounding Rep. Steve Scalise, R-La.