Canada’s proposed new counterterrorism act is unnecessary and would imperil fundamental rights enshrined in international law and the country’s Charter of Rights and Freedoms, Human Rights Watch said today in a letter to the Canadian Senate. Senators should vote “No” on the proposed Anti-Terrorism Act, 2015, known as Bill C-51.

The bill would grant sweeping powers to the Canadian Security Intelligence Agency (CSIS) to disrupt protests it deems unlawful, allow unfettered sharing of individuals’ personal information among 17 Canadian government agencies and with foreign countries, and create a new criminal offense of “advocating or promoting the commission of terrorism offenses in general” that could undermine free speech.

“Canada already has ample and sufficient powers to confront violent extremism,” said Letta Tayler, senior terrorism and counterterrorism researcher at Human Rights Watch. “This vague and overbroad law could trample freedoms at home while tarnishing Canada’s rights-respecting image abroad.”

The bill passed the House of Commons, 183-96, on May 7, 2015. The Senate is expected to vote on the bill the week of June 1. Liberal Party senators have said they will vote against the bill, while the Conservative majority supports it.

The bill would transform Canada’s intelligence service into an operational agency, allowing it to disrupt an exceptionally vast array of activities in the name of national security. The bill explicitly provides for the possibility that it could take measures that would violate the Charter as long as it obtains a warrant in a secret hearing. For activities abroad, the intelligence service would not need a warrant even if it was violating foreign law. Currently the agency can only gather information and pass it to the police.

One provision would let the government place individuals on a no-fly list, while denying them access to some of the evidence it used to make the decision. Another provision would allow judges to restrict access to certain evidence against foreign nationals and other non-citizens in security-related deportation hearings, which already do not meet international fair-trial standards. In addition, Bill C-51 would lower the threshold and lengthen the period for police detention without charge, increasing the risk of arbitrary and unlawful deprivation of liberty.

Prime Minister Stephen Harper proposed the bill after attacks in October 2014 in Quebec and Ottawa killed two Canadian soldiers; in the Ottawa attack a gunman stormed Parliament.

“Canada has a responsibility to protect its people from harm, but this should not be an excuse to dispense with human rights,” Tayler said. “Senators who vote for the Anti-Terrorism Act risk undermining the rights Canadians have long held dear.”