Please click here to sign a petition calling on the nation's largest community foundation to end its financial support for Islamist hate groups.

SVCF's board of directors is turning a blind eye to religious extremists.

In many lines of work, a new job means a slow first day. My first day as the director of the Middle East Forum's Islamist Watch project, however, featured a clash with the Silicon Valley Community Foundation (SVCF), the nation's largest community foundation, which holds over $8 billion in assets.

I previously ran Stand for Peace, a British counter-extremism organization. I know that we face the enormous challenge of media, government and civil society that refuse to acknowledge the extent of Islamist influence over the American Muslim community, and the threat that it poses to our security. My first day was never going to be an easy one.

For several months before my arrival at Islamist Watch, the Forum had attempted to contact SVCF's staff and trustees, urging them to stop funding extremist groups such as the Council on American Islamic Relations (CAIR) and Islamic Relief USA, a branch of the largest Muslim Brotherhood charity in the world. Since 2008, SVCF has given $330,524 to these two Islamist organizations.

The Forum's attempt to explain the extremist links of CAIR and Islamic Relief were rebuffed by SVCF, which refused to address MEF's concerns that they were not funding ordinary American Muslims, but international Islamism, an extreme form of the religion.

SVCF funding of extremists betrays moderate Muslims working to free their faith from the grip of Islamism.

SVCF's unwillingness to stop funding extremists betrays moderate Muslims working to free their faith from the grip of Islamism. So on March 1, the Middle East Forum published a petition that explained the anti-Semitic, homophobic and misogynistic rhetoric that SVCF money is subsidizing.

Regular speakers at CAIR and Islamic Relief events include Hussein Kamani, who advocates sex slavery and calls for adulterers to be "stoned to death"; Jamal Badawi, who tells husbands they have a right to beat their wives; and Siraj Wahhaj, who cites the death penalty for the "disease" of homosexuality. Hardly the proudest product of Silicon Valley ingenuity and liberalism.

You can read our press release and sign our petition here.

Just a few hours after publishing our petition, SVCF responded. You can read their reaction here.

We had urged SVCF to work instead with moderate Muslim groups. Rather than examine the facts, SVCF chose to label our evidence "Islamophobic." The Forum, our Muslim staff and our Muslim allies disagree.

The Forum is not the only organization concerned about CAIR and Islamic Relief. Both CAIR and Islamic Relief are designated as terrorist groups in the United Arab Emirates. CAIR was named by American federal prosecutors as an un-indicted co-conspirator in the 2008 Holy Land Foundation terrorism financing trial. The FBI has banned outreach with CAIR since 2008, and the Anti-Defamation League accuses CAIR of promoting anti-Jewish sentiment.

In a recent article published at National Review, we revealed that Islamic Relief USA is funding a Hamas-linked charity in the Gaza Strip, whose officials have called for Jerusalem to be "free... from the filth of the most dirty Jews." Senior Islamic Relief USA staff have included Omar Shahin, who once preached: "oh (servant) slaves of Allah, there is a Jew behind me; come and kill him."

I have a lot of experience with Islamist groups like CAIR and Islamic Relief. Coming from the United Kingdom, I know exactly how dangerous it is when a society fails to challenge the forces of radicalization and extremism that run the charities, schools, community centers and mosques all across the country. It took Britain over a decade after 9/11 to realize that we had been giving power and money to the wrong people within British Islam, at the cost of thousands of recruits to foreign terror groups, increasing numbers of homegrown terrorists and whole Muslim communities that have segregated themselves from British society and teach their children to hate Jews, Christians, the West and all its values.

It's time to fix our mistakes and properly challenge Islamist forces at home and abroad.

Over the last few years, the British government finally started to realize the terrible mistakes they have made. They cut funding to Islamist groups and refused to meet with them. For many, it feels this insight was too late. In America, the extremism problem is less developed – we have time to fix our mistakes and properly challenge Islamist forces at home and abroad. But we have to start now.

If groups such as SVCF continue to fund the flagship institutions of Islamist extremism, they will further disempower moderate Muslim organizations, contribute towards the growing problem of radicalization, and aid Islamist incitement against Jews, women, homosexuals and Muslim minorities.

Help us show SVCF that by funding Islamist groups, they are not fighting prejudice; they are promoting it. Sign our petition, share it and tell SVCF that they're making a terrible mistake.

Sam Westrop is the director of Islamist Watch, a project of the Middle East Forum.