AND WE'RE GETTING NEW DETAILS ON HOW THEY ARE PREPPING FOR THEIR CRITICAL DEBATE. HERE IS GABE GUTIERREZ. >> Reporter: TONIGHT THE FINAL STRETCH OF THE 2024 PRESIDENTIAL RACE IS UNDER WAY. >> GOOD AFTERNOON, PITTSBURGH! >> Reporter: VICE PRESIDENT HARRIS IS SET TO RETURN TO PENNSYLVANIA ON THURSDAY, CAMPAIGNING WITH PRESIDENT BIDEN THERE JUST YESTERDAY. >> DONALD TRUMP IS TRYING TO PULL US BACKWARDS. INCLUDING BACK TO A TIME BEFORE WORKERS HAD THE FREEDOM TO ORGANIZE. >> Reporter: WHILE FORMER PRESIDENT TRUMP WILL BE IN THE STATE TOMORROW AFTER HOLDING A RALLY THERE JUST DAYS AGO, BLASTING HARRIS FOR CHANGING HER POSITION AND NOW OPPOSING A FRACKING BAN, A KEY INDUSTRY IN PENNSYLVANIA. >> SHE'S VOWED REPEATEDLY THAT WE WILL BAN FRACKING. THE PEOPLE OF PENNSYLVANIA ARE SMART. THEY'RE NOT GOING TO FALL FOR IT. >> Reporter: LATER IN THE WEEK HE'LL HEAD TO WISCONSIN AND NORTH CAROLINA WHERE THE FIRST GENERAL ELECTION BALLOTS WILL BE MAILED OUT THIS FRIDAY IN A RAZOR-THIN RACE. >> SHE HAS A BACKBONE LIKE A RAMROD. SHE HAS A MORAL COMPASS OF A SAINT. THIS WOMAN KNOWS WHAT SHE IS DOING. >> Reporter: TODAY THE FORMER PRESIDENT OFF THE TRAIL BUT ON THE ATTACK. >> I DON'T KNOW HOW PEOPLE CAN VOTE FOR SOMEBODY THAT HAS DESTROYED OUR COUNTRY. THE INFLATION, THE BAD ECONOMY, BUT TO ME, IN A WAY THE WORST IS WHAT THEY'VE ALLOWED TO HAPPEN AT OUR BORDER. >> Reporter: THE NEXT MAJOR MILESTONE IN THE RACE, NEXT WEEK'S DEBATE. A HARRIS CAMPAIGN OFFICIAL TELLS NBC NEWS SHE'LL CONTINUE HER DEBATE PREP THURSDAY IN PITTSBURGH WHILE CAMPAIGN OFFICIALS SAY FORMER CONGRESSWOMAN TULSI GABBARD IS HELPING IN POLICY ATTACKS. BUT TONIGHT HARRIS' TEAM IS STILL CALLING FOR A CHANGE TO THE RULES. DURING THE LAST DEBATE AT THE REQUEST OF THE BIDEN CAMPAIGN, MICS WERE MUTED WHILE THE OTHER CANDIDATE WAS SPEAKING TO PREVENT INTERRUPTIONS. NOW THE HARRIS TEAM WANTS THE MICS UNMUTED AT ALL TIMES. TOMORROW THE VICE PRESIDENT IS HEADING TO NEW HAMPSHIRE WHERE SHE'LL ANNOUNCE A PROPOSAL TO EXPAND SMALL BUSINESS TAX DEDUCTIONS.