presidential power to pressure a foreign leader in hopes of hurting a potential 2020 opponent and helping his own campaign. this hour, i'll talk with congressman peter welch. he's a democrat on the house intelligence committee. and our correspondents and analysts are also standing by. first, let's go to our chief white house correspondent, jim acosta. jim, president trump is refusing to give a straight answer about his contacts with the ukrainian president. >> that's right, wolf. but as you said, cnn has confirmed president trump pressed the president of ukraine to investigate joe biden's son in a call over the summer, and that the call, according to our david shoretel was part of the whistleblower complaint that has rocked the white house this week. the white house is still not commenting on these latest revelations, but earlier in the day, the president did not deny that biden came up during that phone call. all of this is raising questions for democrats as to whether the president attempted to collude with a foreign government, this time ukraine, to impact the 2020 election. >> reporter: sitting in the oval