Up until recently almost all Einsteinians ("later writers" in John Norton's text below) fraudulently used the Michelson-Morley experiment as support for Einstein's 1905 false constant-speed-of-light postulate:

http://philsci-archive.pitt.edu/1743/2/Norton.pdf
John Norton: "In addition to his work as editor of the Einstein papers in finding source material, Stachel assembled the many small clues that reveal Einstein's serious consideration of an emission theory of light; and he gave us the crucial insight that Einstein regarded the Michelson-Morley experiment as evidence for the principle of relativity, whereas later writers almost universally use it as support for the light postulate of special relativity. Even today, this point needs emphasis. The Michelson-Morley experiment is fully compatible with an emission theory of light that contradicts the light postulate."

At present the original fraud seems to have been abandoned (partially due to my activity) but a new version is being advanced. Improved Michelson-Morley experiments now gloriously confirm not just the constancy of the speed of light but "a core component of Einstein's theory of Relativity known as 'Lorentz symmetry,' which predicts that the speed of light is the same in all directions":

http://phys.org/news/2015-09-greater-precision.html
PHYS.ORG: "Researchers from The University of Western Australia and Humboldt University of Berlin have completed testing that has effectively measured the spatial consistency of the speed of light with a precision ten times greater than ever before. The stringent testing also confirmed a core component of Einstein's theory of Relativity known as 'Lorentz symmetry,' which predicts that the speed of light is the same in all directions."

http://www.nature.com/ncomms/2015/15...comms9174.html
"Lorentz symmetry is a foundational property of modern physics, underlying the standard model of particles and general relativity. It is anticipated that these two theories are low-energy approximations of a single theory that is unified and consistent at the Planck scale. Many unifying proposals allow Lorentz symmetry to be broken, with observable effects appearing at Planck-suppressed levels; thus, precision tests of Lorentz invariance are needed to assess and guide theoretical efforts. Here we use ultrastable oscillator frequency sources to perform a modern Michelson-Morley experiment and make the most precise direct terrestrial test to date of Lorentz symmetry.... (...) This order of magnitude improvement over previous Michelson-Morley experiments allows us to set comprehensive simultaneous bounds on nine boost and rotation anisotropies of the speed of light, finding no significant violations of Lorentz symmetry."

Pentcho Valev