As I wrote in While Webb Bleeds, Space Science Hemorrhages, U.S. budget skepticism is going to persist as long as every big project is years behind schedule and far over budget.    The nation that put a man on the moon has since seen fiascoes like the Superconducting Supercollider and now the James Webb Space Telescope.   

A few months ago when I wrote that article, it was 3 years behind and $1.5 billion over budget with no end in sight. The last projection of 2014 and $5 billion in cost was so maddening it launched an outside investigation.  Now it turns out to be even worse: $6.5 billion and September 2015 completion.

A report ordered by Senator Barbara Mikulski, a Maryland Democrat (see Democratic War on Science) said the whole thing was flawed from the beginning, essentially implying the cost and technical issues were understated to get financing started.  

Sure, it's only money, but budgets are limited.  While the JWST continues to flounder smaller projects that wouldn't have engineering problems will be denied funding even longer.  Meanwhile, bureaucrats at NASA are still milking the Hubble, though it had its own technical issues. 
"We've all seen the stunning results that have come out from Hubble," said astronomer and review panel member Garth Illingworth, with the University of California Observatories.
1990 was a long time ago.   As I wrote then, when the JWST project was still a year closer and $1.5 billion cheaper,
  What NASA might need is not a James Webb telescope but an actual James Webb - a guy who took the job with the understanding that NASA was not a political body in business to stay in business, but out to learn about the stars. With no more computing power than a Commodore 64, Webb's NASA launched 75 missions to space, and then the biggest one of all - landing on the Moon.
All these issues tend to fade away once it is working (see: Hubble again) but until then it is going to be an icy reception for big science funding in Congress.