If we listened to his jungle bunny loving nerd, the U.S. still would have been an agrarian, slave-based economy for many decades
Let's assume Jefferson actually doesn't pursue the Louisiana purchase fearing a precedent for expansive federal authority that could undermine states’ rights:
>westward expansion halted to the Appalachians
>Tecumseh’s Confederacy lasts much longer, becomes a more powerful quasi-nation
>Northwest and Indiana territories no longer a priority for settlement remains a frontier, eventually recaptured by Tecumseh; Mississippi river is the furthest any American outpost goes
>intense focus on cash crops fueled by chattel slavery
>Spain exerts more control over Florida, threatens France's holdings in North America
>Westward expansion that was supposed to act as the "safety valve" for slavery is now gone, U.S. now directly competes with Spain for land
>U.S. is merely a "dwarf military" with limited maritime capabilities; so busy dealing with Spain on the water that Barbary pirates are a much bigger threat and virtually ends American sea trade
>slides into global irrelevance
>forced into humiliations treaties with fucking injuns and Spain
all because of NIGGERS
no alternative timeline exists where NIGGERS don't ruin the U.S.!