Old post I know but a lot of these answers here are just simply incorrect.

Socialism and democratic socialism are one and the same because socialism cannot exist without democracy. Bernie calls himself a democratic socialist. What he advocates for is called social democracy, or the Nordic model. Social democrats think that social democracy is good enough. Socialists do not. We don't want well regulated capitalism. We want socialism. But unlike communists and revolutionary socialists, we want to achieve it through gradual, democratic means, through elections and convincing the people to join us. Socialism won't be achieved until late into our lifetimes, but it is inevitable. Right now we must reach the state of a social democracy. But anyone who thinks that the fight ends there, or that we shouldn't go beyond it, is not committed to the cause of progress.

Soviet Union wasn't socialist beyond it's name. It believed in the vanguard party which essentially states some elites should have power over others and have a right to determine what the best interest of the working class is without actually consulting them. Under Stalin it devolved into corporatism and pure statism. Mao's China was guilty of the same, and the DPRK is just a weird sort of quasi-fascist monarchy. Socialism hasn't existed yet on a national scale anywhere.

I'm a Sanderista and I'm all in for Bernie. I'm a committed socialist and when those who haven't really read much about socialist theory try to say socialism is about big government, or that socialism is just well-regulated capitalism, or that socialism doesn't work, I get very aggravated. It's really intellectually lazy and it ignores 180 years of socialist theory. Bernie is a big step toward it. He isn't the end of progress, and neither is the system of Sweden the end goal of socialism.

Not all social democrats are socialists, but many democratic socialists are for social democracy as a stepping stone in economic evolution