Politics makes strange sidewalk fellows.

Both Occupy Worcester and the Worcester Tea Party will participate in a demonstration against the National Defense Authorization Act from 3 to 7 p.m. today in front of the Harold D. Donohue Federal Building, 595 Main St. Both groups are urging members to attend the event, which is part of a national day of protest.

While members of the two organizations do not usually support the same political candidates, the two anti-establishment groups have found common ground on this issue.

Occupy Worcester will be there beginning at 3 p.m. The Worcester Tea Party urges its members to attend from 5 to 6:30 p.m.

Both groups fear that the federal law enacted this year threatens civil liberties, saying that it permits the indefinite detention of American citizens accused of supporting terrorism.

�If we are to be a movement about principles, then we must stand up against these assaults� on basic freedoms, said Kenneth Mandile, head of the Worcester Tea Party, �regardless of who is standing next to us.�

Jonathan Noble of Occupy Worcester, which organized the event, said, �Occupy Worcester will stand in solidarity with groups and movements across the country.� There will be a reading of the Bill of Rights at the protest, he said.

There was fierce debate in Congress as to the meaning of the language added this year to the defense authorization act.

But Occupy Worcester is pretty clear about it. �This year�s bill contains language that gives the military the authority to indefinitely detain anyone who is a suspect in a terrorism investigation or has suspected terrorism ties indefinitely without trial or any form of due process.

�This means that any American citizen can be arrested and held for an indefinite period, possibly for their entire lives, simply because someone in the military or the government suspected them of having been linked to a crime.�

Noting that Occupy Worcester organized the protest here, The Worcester Tea Party said in a statement, �As much as we may disagree with the goals and tactics of this organization, we feel that this issue is so important that these differences should be put aside and we should stand together as citizens to protest this attempt to circumvent the Constitution.�

Mr. Mandile said, �It would be easy to stay at home on Friday because you do not fear indefinite detention of yourself or your family, but it is important to fight every time Washington hacks off another piece of the Constitution.

�Most of us accepted a diminished Constitution when the Patriot Act and the Military Commissions Act were passed. We should have spoken up then.

�Now we have NDAA and the potential for SOPA (Stop Online Piracy Act), PIPA (Protect IP Act) and the EEA (Enemy Expatriation Act). Each of these is an assault on basic rights that our leaders have sworn to protect.�

The tea party warns, �Despite assurances from Republican and Democrat congressmen and senators, the 2012 NDAA allows for the indefinite detention of United States citizens.�

Legislation that has united the tea party and Occupy Worcester pitted U.S. senator against U.S. senator and even Republican senator against Republican senator. Senators disagreed on whether it is the first time legislation permitted the government to arrest citizens inside the United States and hold them indefinitely in military custody or whether it already had that authority.

Without coming to agreement on what previous law means, the senators voted 99-1 on Dec. 1 to say that the legislation will not affect �existing law� on the arrest of people within the United States.

There was disagreement not just on what the law is, but what it should be. Sen. Mike Lee, R-Utah, said terrorism suspects should retain their �fundamental civil liberties� to protect the country�s founding principles.

But Sen. Lindsay Graham, R-S.C., quoted in the New York Times, said it would be �crazy� to exempt from battlefield-style detention American al-Qaida suspects who are arrested inside the country. They should be interrogated without the protection of the civilian criminal justice system to stop further attacks, he said.

Citizens who are suspected of enlisting in the terrorist organization open themselves �to imprisonment and death,� Mr. Graham said, adding, �And when they say, �I want my lawyer,� you tell them: �Shut up. You don�t get a lawyer. You are an enemy combatant, and we are going to talk to you about why you joined al-Qaida.� �