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The leading determination of the Hubble constant comes from observations of Cepheid variables by HST calibrated by parallaxes from Gaia. This measurement is in tension with the value predicted by LambdaCDM calibrated by the CMB. The suggested limitation of the current cosmological model is a clue we must be pursue. The sample of Milky Way Cepheids observed by HST offers the means to build a still superior distance ladder and reach the long-targeted legacy goal of a 1% measurement of H0. Unfortunately comma an unexpected Gaia anomaly has reduced the available precision of a Cepheid calibration sample planned well before Gaia.s launch. We thus propose an HST SNAP program to double the current sample by imaging all remaining Milky Way Cepheids in Gaia.s ''sweet spot.. for the greatest gain comma using the same WFC3 bands for their extragalactic counterparts to nullify the effects of calibration errors along the distance ladder. The MW variables were selected to have the highest signal-to-noise in the measured parallaxes comma the lowest reddening comma to be fainter than Gaia.s saturation limit comma and with periods that directly calibrate extragalactic Cepheids and H0. The proposed sample has also been cleansed of astrometric binaries which degrade parallax precision comma newly revealed by Gaia.s EDR3 (December 2020). Together comma Gaia and HST comma each doing what they do best comma can achieve what neither can do alone. Collecting these observations will lay a cornerstone for a 1% determination of H0 and continue to steadily advance our knowledge of what appears to be a new feature in the cosmological model.