$1.5 trillion is less than what was spent on the Iraq war, and just two years of US military spending. We can make it work without simplistically raising everyone's taxes by $1.5T/everyone. The hardest step is to change people's political priorities so that they actually include making more people better off.

Oh, and to answer your actual question, yes, I'd much rather have $300 of my tax bill every paycheck go towards the "making education free for everyone" fund rather than the "blowing up a kid hiding in a hole with an AK47" fund.

And what if we don't decrease the military spending? Are you happy to pay the extra?

Sure, if we're setting aside reality, and pretending that the only possible way to fund this is with a nation-wide, flat, non-progressive federal income tax increase for the full amount, I'd still be fine with it. Not sure what that adds to the discussion, since that's not even remotely how something like this would actually be paid for.