Republican U.S. Sen. Susan Collins of ME says the House impeachment inquiry will likely mean that action on other important bills, including the budget, will be delayed.
The president has repeatedly maintained that his phone call with the Ukrainian president was "perfect" and that he had asked Zelensky for help to investigate the alleged corruption around Biden's dealings.
The whistle-blower's complaint claimed that Trump was "using the power of his office to solicit interference from a foreign country" in the 2020 US election given that Biden is perceived as a possible Democratic candidate to face the incumbent Republican president.
"Although the House is still gathering information and evidence and has a long way to go, my prediction is that articles of impeachment will come before the Senate", she says.
"The president should not have raised the Biden issue on that call, period".
Congress members can not be impeached, however, the Constitution allows each chamber of Congress to create their own rules to "punish its Members for disorderly Behaviour" or "expel a member".
Trump has claimed that Biden, as vice president, forced out Shokin to protect his son.
Leading up to the call, Trump had withheld almost $400 million in military aid and White House staff had later allegedly sequestered a record of the discussion in a computer server meant for highly-classified material.
The timing of the whistleblower's contact with Democrat staff was also reportedly not revealed.
The California Democrat defended his comments amid backlash from Republicans at the time, saying: "Of course, the president never said, 'If you don't understand me I'm going to say it seven more times, ' my point is, that's the message that the Ukraine president was receiving in not so many words".
The Republican president has said, without evidence, that Schiff helped draft the complaint, and that the effort was "meant to be at least part in parody".
This week a second intelligence official is thought to be considering filing a formal whistleblower complaint about Trump's dealings with Ukraine.
House Democrats are considering taking dramatic steps to protect the anonymity of a whistleblower who filed a complaint against President Donald Trump, The Washington Post reported Monday. This second person has reportedly been interviewed by the head of the Intelligence Committee, but has not yet spoken with Congress.