From The Catholic Spirit, the newspaper and site of the Archdiocese of St. Paul and Minneapolis, comes this. With my emphases and comments:
To assist statewide efforts to defend and define marriage in the Minnesota Constitution, Archbishop John Nienstedt has issued a prayer intended for use as part of the Prayers of the Faithful at Mass.
The archbishop also encourages use of the prayer in eucharistic adoration chapels so worshipers can pray for the success of the state marriage amendment and all efforts to strengthen marriage, according to a letter posted on the archdiocesan website at http://www.archspm.org. He also is calling on Catholics in the archdiocese to embrace Fridays as a day of prayer and sacrifice for the success of the amendment effort. [You've got to know that, now that they are going to move this even more into the realm of prayer, the forces of Hell itself will being to attack the Archbishop and all who support this effort even more viciously.]
[NB] The amendment, supported by Minnesota’s Catholic bishops, will appear on the 2012 ballot. It will ask voters: “Shall the Minnesota Constitution be amended to provide that only a union of one man and one woman shall be valid or recognized as a marriage in Minnesota?”
“The current struggle to defend and define marriage within our civil constitution demands a three-fold approach,” Archbishop Nienstedt said.  “We must educate our fellow citizens on the meaning and good of marriage.  We must actively and resolutely promote widespread participation among our fellow believers in the support of a marriage amendment. And, most importantly,  we must pray and offer sacrifice for the success of all endeavors that seek to protect and promote marriage.”
Here is the prayer:
Through the powerful intercession of the Holy Family, grant to this local Church the many graces we need to foster, strengthen, and support faith-filled, holy marriages and holy families.
May the vocation of married life, a true calling to share in your own divine and creative life, be recognized by all believers as a source of blessing and joy, and a revelation of your own divine goodness.
Grant to us all the gift of courage to proclaim and defend your plan for marriage, which is the union of one man and one woman in a lifelong, exclusive relationship of loving trust, compassion, and generosity, open to the conception of children.
We make our prayer through Jesus Christ, who is Lord forever and ever. Amen.
There is a combox over there, too.