Transcript for Democrats zero in on Trump’s timeline during impeachment trial
The latest on the impeachment trial of president the house managers will wrap up their case against the president today after using the president's own words against him yesterday and taking on the president's argument by mounting their strongest defense yet of Joe Biden. Our senior congressional correspondent Mary Bruce is on capitol hill, Mary, the big question, are these arguments making any impact on senate Reporter: Well, George, I can tell you from spending time inside the chamber many Republicans are paying close attention. They are taking detailed notes following closely as the Democrats make their case. Now, some I have talked to, some Republicans say they are frustrated. They've heard this all before, but many Republicans ait the Democrats are giving them things to think about. If right doesn't matter, we're lost. If the truth doesn't matter, we're lost. Reporter: Overnight democratic prosecutor Adam Schiff with an emotional appeal. You know that what he did was not right. No constitution can protect us if right doesn't matter anymore. Reporter: A passionate conclusion after Democrats hammered their case for eight hours. When it came down to choosing between the national interests of the country and his own personal interests, his re-election, president trump chose himself. Reporter: The Democrats zeroing in on the timing saying trump didn't start pushing Ukraine to investigate Joe Biden until 2019. Right when the polls showed the former vice president was his biggest threat. Those polls do show a powerful motive that Donald Trump had, a motive that he didn't have the year before or the year before that. Reporter: Trump's now infamous phone call with the Ukrainian president was in July of 2019, two years after trump took office, but just three months after Biden entered the race. Even president trump knew there was no basis for this investigation, never once raised the issue. It wasn't until Biden began beating him in the polls that he called for the investigation. Reporter: Congresswoman Sylvia Garcia set out to dismantle the white house's repeated allegations against Biden. The allegations against vice president Biden are groundless. There is simply no evidence, nothing, nada in their record to support this baseless allegation. Reporter: Trump's legal team argues abuse of power is not a crime and, therefore, not impeachable. The actions of the president do not reach that level. You still have to meet basic fundamental constitutional obligations and they haven't. Reporter: But members of trump's own defense team and his attorney general bill Barr have argued the opposite, that you don't need a crime to impeach. Democrats even playing this old video of trump's top ally, senator Lindsey graham from the Clinton impeachment trial. I think that's what they meant by high crimes. Doesn't even have to be a crime. Reporter: Democrats have one more day to make their case. Some Republicans say they've had enough. They start repeating themselves as if you could impeach by just kind of repeating the same thin. Reporter: But other key Republicans are listening closely, senator Lamar Alexander saying the Democrats have done a good job presenting and we have a lot to consider. Democrats now hopeful it's a sign they're persuading some Republicans to support their case. Now it is up to us to do something about it. To make sure that a president -- that this president cannot pursue an objective that places himself above our country. Reporter: Democrats now have eight hours left on the clock. Then tomorrow according to the current schedule it will be the trump team's turn. They will then have three days' total to make their case and respond but, George, sources tell us they may opt for a shorter session on Saturday so they can make the bulk of their argument next week when more people are likely to be tuning in. Let's bring in Jon Karl for more on this right now and, Jon, we did see the Democrats yesterday, really talk about Biden more than they have before because they want to take on the president's claim he was pursuing corruption, not going after a political rival and his lawyers yesterday suggested this could backfire on the Democrats? Reporter: Well, absolutely. Because they think this is an you can bet, George, that when the president's team comes to make their case, a big part of the case will be to eviscerate Joe Biden, to take on Joe and hunter Biden and believe in making this defense, the Democrats have basically called for this, so you will see the president say -- first the president's team say he did nothing wrong. Even if he did what's alleged it's not impeachable and a bulk of the presentation to be taking on Joe Biden. Mary just said we think now the session is likely to happen tomorrow but the white house has been kind of all over the map on that, even suggesting at some point they didn't want to meet on Saturday at all because no one would be watching. Reporter: The latest I have on this this morning from somebody close to the president's team is that they expect that they will be in session on Saturday. It will be short. Probably a couple of hours and they will wait till Monday to make the bulk of their case. Okay, Jon Karl, thanks very much. I know you'll join us for the live coverage. I'll anchor with our political and legal team starting at 1:00 eastern this afternoon.
This transcript has been automatically generated and may not be 100% accurate.