Marriage advocates are mobilizing to defend the federal Defense of Marriage Act, which has been targeted by congressional backers of so-called “homosexual marriage.”

The act defines marriage as a legal union between one man and one woman for purposes of all federal laws, and gives federal protection to similar legislation passed in most U.S. states to define marriage as an institution that can involve only one man and one woman.

It’s tedious to have to repeat, every time the issue of attempting to redefine marriage arises, that DOMA and these state definitions of marriage simply codify the understanding shared by human society throughout history — that marriage is a heterosexual-only institution. And this understanding is the only basis upon which this fundamental social unit can be protected against efforts by the homosexual lobby to redefine marriage legally to include same-sex relationships, to the detriment of the common good and especially to the detriment of the best interests of children.

Moreover, there is nothing discriminatory about DOMA or about the state legislation DOMA also serves to protect. Every American adult possesses the same right to enter into marriage with a member of the opposite sex.

But while it’s tedious to restate these basic facts, it must be done given that homosexual activists and their allies in Congress are launching another major assault on the institution of marriage — and on the religious freedom rights of the majority of Americans who oppose the agenda of the homosexual lobby.

Go here to access some material the U.S. bishops have posted at the USCCB website, in support of protecting marriage against redefinition to include homosexual “marriage.” 

Here is the text of a public letter released today by Brian Brown, executive director of the National Organization for Marriage, detailing what’s at stake here and what supporters of marriage need to do:

The attack on DOMA has begun.

Today, Congressman Jerry Nadler (D-NY) will introduce a bill to repeal the Defense of Marriage Act—the only federal law protecting the marriage statutes of 44 states. Reports indicate he has at least 69 co-sponsors in this effort to undercut state marriage laws.

We’ve known this day would come. President Obama has been advocating the repeal of DOMA since his first day in office. Gay marriage activists have debated the strategy and timing for pushing the bill in Congress.

And we’re ready. Already, we are more than 500,000 strong as Americans from every walk of life have joined our ranks to stand firm against radical efforts to force same-sex marriage in every state. Our goal is 2 million Americans by the end of 2010. If each of us were to tell just three friends about, we’d reach our goal in mere days.

Now it’s time to speak truth to power! Gay marriage advocates are divided on DOMA—even Rep. Barney Frank thinks the DOMA repeal bill is overreaching and has refused to support it. Now is our chance to send a clear message to Congress that will galvanize opposition to the DOMA repeal, and help sway those who are on the fence. The message is simple: Don’t mess with marriage.

Just a few years ago, gay marriage advocates spoke of “state’s rights” and a “gay marriage experiment” in a handful of states. Obviously, they didn’t believe a word of it, and today they want to force same-sex marriage on every state in the nation, “like it or not.”

Marriage isn’t about inside-the-Beltway opportunism, or scoring political points. It’s about honesty and integrity. Protecting children and religious liberty.

The need is urgent. I’m asking you to do three things right now:

1) Visit and send a message to Washington. Use our online form to contact your Senators, Congressman, as well as congressional leadership, and tell them “Don’t Mess with Marriage.” Even if you’ve emailed before, let’s flood the Capitol with phone calls and emails today, urging our congressmen to oppose Rep. Nadler’s DOMA repeal bill.

2) Tell three friends about this new threat to DOMA, and ask them to join us at today! Or just forward this email to people in your address book—it’s simple, fast, and amazingly effective. We’re already 500,000 strong, and together we can stop this bill in its tracks!

3) Help support our TwoMillionforMarriage campaign today. Over the next six months, we need to raise another $1.5 million to fully fund our multi-faceted campaign to recruit 2 million Americans to join us in protecting DOMA. Using TV, radio, internet, telephone, email and direct mail efforts, we are identifying tens of thousands of new marriage activists who have never before been politically involved, but who care about marriage and are willing to do what it takes to stop courts and politicians from trampling the will of the American people. Your gift of $25, $50, or even $1000 if you’re able, will help ensure that we reach our goal. Click here to make a secure online donation today.

I’m simply in awe at the outpouring of encouragement and new supporters we keep seeing every day. To those of you who have been with us for a long time—thank you! And keep up the good work. Together we’re getting the message out and making a difference all across the country. And for those of you new to our efforts—Welcome! We’re so glad you’ve joined us, and look forward to working together in this fight for marriage.

The threat is real, and increasingly urgent. Please take action right now. Don’t put it off. Let’s make sure Congress gets our message loud and clear today.