At their first, and possibly only, debate, Vice President Kamala Harris and former President Donald J. Trump will have a chance to paint the picture of their opponent that they want voters to see.

Ms. Harris has signaled that she will portray Mr. Trump as a billionaire out for only himself who will strip Americans of fundamental rights. Mr. Trump has made clear that he sees Ms. Harris as a lightweight who is too liberal to lead America and who is inextricably tied to the policies of President Biden.

Here is how the two candidates may go after each other at the ABC News debate on Tuesday evening in Philadelphia.

Harris’s main potential lines of attack at the debate

Ms. Harris, 59, casts herself as representing the future of American government and Mr. Trump, 78, as a relic of the past. She will press her advantage on favorable issues, most obviously abortion, while seeking to counter Mr. Trump’s attacks on topics where she is weaker, like the economy and immigration.