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The Imaging X-ray Polarimetry Explorer (IXPE) has opened a new observational window in high-energy astrophysics by delivering the first imaging polarimetric data in the X-ray band. For the first time in the X-ray domain, this capability provides direct access to the emission geometry, magnetic-field structure, and radiative processes in compact objects. By adding polarization as an observable, IXPE allows long-standing degeneracies between accretion- and jet-dominated high-energy emission models to be tested observationally. In this talk, I will briefly introduce the IXPE mission and its polarimetric measurement technique, along with key scientific highlights from the first few years of the mission. I will then focus on our recent IXPE observations of the nearby radio galaxy 3C 84, the brightest galaxy in the Perseus Cluster. These observations constitute the first X-ray polarization measurement of 3C 84 and were obtained through IXPE’s longest observation to date. Using IXPE data together with inputs from other NASA missions, including Chandra, NuSTAR, and Swift, we detect a statistically significant X-ray polarization degree of 4.2+/-1.3%, with the electric vector position angle closely aligned with the parsec-scale radio jet in 3C 84. The measured polarization amplitude and orientation strongly disfavor scenarios dominated by accretion-disk corona emission, dusty-torus scattering, or external Compton processes. Instead, the results favor synchrotron self-Compton emission from relativistic electrons in an ordered magnetic field located downstream in the jet. This interpretation is independently supported by contemporaneous optical, millimeter, radio, and gamma-ray polarization and variability measurements. Together, these results provide the clearest evidence to date that X-rays from radio galaxies are jet-dominated and can be produced through Compton scattering of jet synchrotron photons. I will conclude with a brief outlook on forthcoming work that further connects jet structure and high-energy emission, and discuss how these results advance our understanding of the origin of X-rays in supermassive black hole jets.