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Observations of Cepheids with HST show the Universe is expanding significantly faster than expected under the assumption of LCDM calibrated with measurements from the early Universe. The significance of this remarkable result has reached 4-6 sigma and passed numerous tests of robustness. Improving the measurement of the Hubble constant now can move us beyond merely detecting this discrepancy to identifying its origin. We propose to obtain HST photometry of Cepheids hosted by open clusters in the Milky Way whose large number of stars provide the highest parallax precision available in Gaia EDR3 comma a factor of more than three better than what is possible for individual Cepheids. To fully exploit these Cepheids to calibrate the distance ladder we propose to observe these Cluster Cepheids with spatial scanning and the same WFC3 three-band photometric system used for extragalactic Cepheids to nullify the effects of photometric zeropoint errors along the distance ladder. This program will surpass the best available calibration of the distance ladder to enable a 1% measurement of the Hubble constant and increase its leverage for identifying the source of the discrepancy. Gaia and HST comma each doing what they do best comma can continue to steadily advance our knowledge of what appears to be a new feature in the cosmological model