What makes you think the government has any concrete evidence they could easily show/explain to the public?
Sure, statistically and knowing what we know about the universe, there's life out there SOMEWHERE.
But considering we still haven't figured out how to get one planet away from where we are, what on Earth makes you think we've reached a point where we have concrete visual or aural proof of another set of life forms out there somewhere?
And again, WHAT motive other than "omg da government is keepin' secrets conspiracy" would the government have to hide the existence of aliens from the public? If anything it would give the people a lot of FAITH in our government if they came out and said "We're the first to discover alien life!"
Every time they discover something on Mars right now that could indicate life is out there, or used to be out there, it's all over the news. Nothing is being hidden from you. Like Jonny said, focus on the actual problems in our government (like, you know, the fact that they're spying on all of us) instead of making up stories about aliens.
