International leaders convened in Washington, D.C., for the launch of the NATO Summit Tuesday, paving the way for a crucial opportunity for host President Joe Biden to prove to critics he is fit for a second term. The three day event’s key initiative to drum up support for Ukraine in its war against Russia will likely be overshadowed by questions swirling around Biden’s ability to defeat Donald Trump in the November election, following the 81-year-old president’s unnerving debate performance June 27. “Journalists attending President Biden’s summit press conference will likely not ask one quest…