Americans seem to favor some Mars initiative by a 74% to 26% vote. But that is because they go to films like The Martian, and think, heck, why not. They're mostly delusional.
As Melies more than a century ago, we again are faced with a desire without capability: simply, engineers have not yet perfected the technology to send humans safely to Mars and back, and won't for some time to come. Second, there is no compelling reason to do so. If, say, China and Russia suddenly form a coalition, and begin spending hundreds of billions annually to claim Mars because it has a strategic or resource value that would mean the end of the USA, sure, we will be forced to do the same. While Musk will have millions going to Mars in less than 20 years, China and Russia could well have been as bullish, but the best they currently offer are similar plans that sometime between 2040 and 2060 they hope to send a crew to the Red Planet. Good luck Elon.
Brummbaer of life on Mars.
James Webb Space Telescope will eventually cost $10 billion just by itself, but we have been jerking this project along for two decades and should have it in space hopefully in 2018, so send it out. But that should be it for a while. Major hardware expenditures should be kept to a bare minimum. The problem with this policy, though, is that as aerospace companies do the heavy lobbying for NASA (for they get most of these funds), deleting this pork item will only convince Congress to further deplete the NASA budget.