FOREGROUND CONTAMINATION PLAYS AN INCREASINGLY CRITICAL ROLE IN THE INTERPRETATION OF COSMIC MICROWAVE BACKGROUND (CMB) ANISOTROPY MEASUREMENTS. WE PROPOSE TO INVESTIGATE HOW MODELING ERRORS MAY CONTRIBUTE TO TENSIONS CURRENTLY OBSERVED BETWEEN THE WMAP AND PLANCK SPACE MISSION DATA AND WITH OTHER COSMOLOGICAL MEASUREMENTS. WE WILL ASSESS THE IMPACT OF POLARIZATION FOREGROUND ASSUMPTIONS ON DETERMINING THE CMB OPTICAL DEPTH TAU A KEY PARAMETER FOR BOTH UNDERSTANDING COSMIC REIONIZATION AND FUTURE EFFORTS TO MEASURE NEUTRINO MASS. WE WILL EXPLORE CURRENT CONSTRAINTS ON VARIATION OF THE HIGH-LATITUDE SYNCHROTRON SPECTRAL INDEX AND IMPLICATIONS FOR CMB STUDIES INCLUDING B-MODE SEARCHES FOR PRIMORDIAL GRAVITATIONAL WAVES. WE WILL REVISIT THE PLANCK 2015 TEMPERATURE POWER SPECTRUM FOREGROUND MODELING AND INVESTIGATE THE EXTENT TO WHICH MODELING ERRORS COULD BIAS COSMOLOGICAL PARAMETERS FROM SMALL ANGULAR SCALES AND CONTRIBUTE TO THE APPARENT 2.5-3 SIGMA DISAGREEMENTS WITH SOUTH POLE TELESCOPE CMB DATA AND VARIOUS LOW-REDSHIFT OBSERVATIONS. COMBINING FITS TO REAL DATA WITH DEDICATED SUITES OF SIMULATIONS WILL ENABLE US TO QUANTIFY THE IMPACT OF FOREGROUND MODELING IMPERFECTIONS AT THE LEVEL DEMANDED BY PRECISE MODERN CMB MEASUREMENTS.