 Harrison spoke with MSNBC's Morning Joe this morning in an effort to rally support. His comments come as a growing number of Democrats are calling for Biden to step aside and let another candidate face former President Trump for the White House. The president is scheduled to meet with Ukrainian President Volodymyr Zelensky later today as the NATO summit wraps up in Washington, D.C. It comes after the 75-year-old alliance approved a joint communique Wednesday affirming Ukraine is on an irreversible path to NATO membership.