According to Reuters the investigation has been given only seven staff members and as a result progress has been sluggish and minimal.
A weak Senate investigation could renew calls by some Democrats and other Trump critics for a commission independent of the Republican-led Congress to investigate the allegations.
The intelligence committees of the Senate and House of Representatives have taken the lead in Congress in examining whether Russia tried to game the election in Republican Trump’s favour, mostly by hacking Democratic operatives’ emails and releasing embarrassing information, or possibly by colluding with Trump associates.
Previous investigations of national security matters have been much larger in terms of staffing according to a review of official reports produced by those inquiries.
The House committee formed to investigate the 2012 attacks on a US diplomatic mission in Benghazi, Libya, that killed four Americans had 46 staffers and eight interns.
The Senate Intelligence Committee’s years-long study of the CIA’s “enhanced” interrogation techniques during President George W. Bush’s administration had 20 staff members, according to the panel’s official report.
The special commission separate from Congress that reviewed the intelligence that wrongly concluded former Iraqi President Saddam Hussein possessed weapons of mass destruction ahead of the 2003 invasion of Iraq involved 88 staffers.