WASHINGTON — After months of buildup, Hillary Rodham Clinton finally takes center stage as the star witness in the Republican-led investigation into the deadly 2012 attacks in Benghazi, Libya.

Clinton, the Democratic front-runner for president, testifies from a position of political strength as her potential rival for the nomination, Vice President Joe Biden, announced Wednesday that he will not jump into the presidential race and she rides the momentum of a solid debate performance.

Meanwhile, the Benghazi committee is on the defensive as the panel’s GOP chairman scrambles to deflect comments by fellow Republicans that the inquiry is aimed at hurting Clinton’s presidential bid.

Even so, Clinton faces a formidable challenge as she tries to explain security lapses at the U.S. diplomatic compound in Benghazi, the slow military response to the violence and the Obama administration’s changing narrative about who was responsible for the attacks that killed four Americans, including U.S. ambassador Chris Stevens, and why the attacks were launched.