Massachusetts Sen. Elizabeth Warren said Thursday she was not thinking "in terms of the politics" when asked if she was worried discussions of former Vice President Joe Biden in the ongoing impeachment trial were strengthening Biden's presidential bid.

Democrats allege President Donald Trump abused his office by directing a pressure campaign for Ukraine to announce an investigation into Biden and his son, Hunter, in exchange for $400 million in US security aid and a White House meeting. Trump, Democrats say, then stonewalled congressional investigators to cover up the misconduct. There is no evidence of wrongdoing by either Biden, and Joe Biden has repeatedly defended his son and himself.

CNN's Dana Bash asked Warren about the Democratic argument that the reason Trump pressured Ukraine was because Biden was doing well in the polls and posed a threat to Trump's reelection. Bash asked Warren if that was concerning to her politically, since Biden's main pitch to voters on the campaign trail is that he is the best candidate to beat Trump in November.

"No, I don't think of this in terms of the politics," Warren said.

"I think of it in terms of, I think the way this argument was framed was to say that so long as Donald Trump didn't see Joe Biden in the presidential race then he didn't care about an investigation in Ukraine," Warren said.

"In other words, he was not interested in corruption for its own sake, whatever kind of corruption might be going on in Ukraine, but the minute Joe Biden appeared to pose some kind of political threat, then all of a sudden Donald Trump is in it," Warren said.

Warren and fellow 2020 Democrats Vermont Sen. Bernie Sanders and Minnesota Sen. Amy Klobuchar are absent from the campaign trail with less than two weeks remaining until the Iowa caucuses as they serve as jurors in the Senate impeachment trial.

Biden and other Democratic candidates, meanwhile, are holding campaign events in the state in the final days before the February 3 caucuses.

Electability and being best positioned to beat Trump in the general election have been the central components of Biden's pitch to voters in the crowded Democratic primary.

Biden released an ad last week that shows a montage of Trump saying Biden's name, followed by a narrator declaring, "Donald Trump has made it clear he's got Joe Biden on his mind because Trump knows Biden will beat him in Pennsylvania, Michigan and Wisconsin -- the states we need to take back the presidency."

A CNN poll released Wednesday shows a plurality of Democrats say Biden has the best chance to defeat Trump — 45% say so of Biden, compared with 24% for Sanders, 8% for Warren, 7% for former New York City Mayor Michael Bloomberg and 4% for former South Bend, Indiana, Mayor Pete Buttigieg.

The same CNN poll marked the first time Biden has not held a solo lead in CNN's national polling on the race, with Sanders joining Biden in a two-person top tier above the rest of the field. Twenty-seven percent of registered voters who are Democrats or Democratic-leaning independents back Sanders, while 24% favor Biden. The margin between the two is within the poll's margin of sampling error, meaning there is no clear leader in this poll.