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Previous observations have not been able to exclude the possibility that hightemperature active region loops are actually composed of many small scalethreads that are in various stages of heating and cooling and only appear to bein equilibrium. With new observations from the EUV Imaging Spectrometer (EIS)and X-ray Telescope (XRT) on \textit{Hinode} we have the ability to investigatethe properties of high temperature coronal plasma in extraordinary detail. Weexamine the emission in the core of an active region and find three independentlines of evidence for steady heating. We find that the emission observed in XRTis generally steady for hours, with a fluctuation level of approximately 15% inan individual pixel. Short-lived impulsive heating events are observed, butthey appear to be unrelated to the steady emission that dominates the activeregion. Furthermore, we find no evidence for warm emission that is spatiallycorrelated with the hot emission, as would be expected if the high temperatureloops are the result of impulsive heating. Finally, we also find thatintensities in the "moss", the footpoints of high temperature loops, areconsistent with steady heating models provided that we account for the localexpansion of the loop from the base of the transition region to the corona. Incombination, these results provide strong evidence that the heating in the coreof an active region is effectively steady, that is, the time between heatingevents is short relative to the relevant radiative and conductive coolingtimes.

Evidence for Steady Heating: Observations of an Active Region Core with Hinode and TRACE