The half-hearted expression of support by the American Muslim Taskforce on Civil Rights and Elections (AMT) reflects Muslim anger over many of the Bush administration's high-profile policies.
These include the invasions of Afghanistan and Iraq, as well as domestic security laws which community leaders say target Muslims.
America's seven million Muslims are a potential swing-voting bloc in key battleground states such as Florida, Michigan, Ohio, Pennsylvania, and Wisconsin.
"(AMT) is calling on Muslims nationwide to cast a protest vote for Senator John Kerry," the Islamic umbrella group said, expressing "disappointment" with an "insensitive" Bush administration.
"Today, American Muslims are being treated like second-class citizens. Unfortunately, the Bush administration has been insensitive to the civil liberties and human rights of American Muslims, Arab-Americans and South Asians."
However, the AMT said its support for Kerry was a tactical move "to help restore liberty and justice for all".
"While the Kerry campaign has critiqued a number of Bush administration polices, it has so far failed to explicitly affirm support for due process, equal justice and other constitutional norms.
"We are also disappointed that his campaign has shied away from expressing unambiguous support for principles enshrined in the US Constitution that prohibit use of secret proceedings and secret evidence.
American Muslims are a potential
important swing voting bloc
"Mindful of disagreements with Senator Kerry on some domestic and international issues, including the war in Iraq, we are willing to work with him to help restore due process and equal justice in accordance with the US Constitution."
A string of polls, taken before and after the endorsement decision, show most Muslims will back the Massachusetts senator over the Republican incumbent on 2 November.
The overarching issues for most Muslim voters are civil liberties and foreign policy, especially the domestic Patriot Act, the Israeli-Palestinian conflict and the situation in Iraq.
Support for Nader
A poll released this week by the Council on American-Islamic Relations put support for Kerry among likely US Muslim voters at 80%, compared to a mere two per cent for the president, and 11% for independent candidate Ralph Nader.
Many in the grassroots community and even the leadership favour Nader, but not enough to risk a Bush victory. A long-shot, Nader is only on the ballot in 34 of 50 states.
"A lot of Muslims want to vote on principle for Nader," said community activist Haaris Ahmad on the sidelines of a Muslim election forum in suburban Detroit this month.
"Today, American Muslims are being treated like second-class citizens. Unfortunately, the Bush administration has been insensitive to the civil liberties and human rights of American Muslims"
"Most of the community is not excited about voting for Kerry. He hasn't offered us much of an alternative to Bush. He hasn't reached out to us. Unfortunately, we have no choice."
Both the Democrats and the Republicans say their policies will benefit American Muslims.
The Democrats have promised to uphold constitutional rights and protections which they say have been overlooked to target Muslim Americans.
They have pledged to amend the Patriot Act, end racial profiling and protect workplace religious freedom.
And they say they will win the peace in Iraq by working with Muslim countries, and make peace between the Israelis and Palestinians a priority.
The Republicans, meanwhile, have pledged to build on the Patriot Act to strengthen intelligence and law enforcement to protect the country from "terrorists".
Bush is deeply unpopular with
They say the US has already liberated 50 million people - mainly Muslims - from "despotic, totalitarian regimes in Afghanistan and Iraq".
And they predict they will transform the Middle East based on America's values of compassion, freedom and democracy.