Yes there was hacking at the election and it was probably enough to steal the election from Hillary Clinton, but there are bigger reasons why we lost and are losing all over the country.
1. Hillary Clinton: A nationwide concerted effort was made to smear her name and paint her as a conniving liar that has been going on since she was the first lady and dared to comment on Healthcare. Nothing competent was done to counter this action. While no one could have guessed at the time that she would go on to be the Democratic nominee for President for 2016, anytime effort of that level is spent and no counter is made, it will hurt the Democratic Party. We just do not know when or how at that time.
2. The Democratic Party stands against the Republican party. Everything has gone polar and the Republican Party has an identity that resonates with their base. The Republicans are pro-life, pro-white, pro-christian, and pro-American (also known as anti-abortion, anti-muslim, anti-minorities, and anti-immigrants). The Democratic party is simply known as the one that is against the Republican Party. An attempt must be made to forge an identity specific to the Democratic Party that does not require the Republican Party for it to exist. The start they have made with a strong economic plan is just that, a start. They need to find out what the voters want and what can be done to create an identity out of voters desires. A good start would be building a strong middle class, increasing healthcare while decreasing individual costs, and using government to benefit all citizens.
3. Propaganda must be countered and it must be countered with effective messages. This requires the identity from part 2. Money must be spent to compensate for the money spent but not in such a way as our values are destroyed in the process. You cannot allow a message to be sent out and make no response or make a weak response. This is the age of social media and any messages that resonate with the voters gets sent out en mass and immediately.
As for hacking the election, Congress needs to take a firm stance, investigate all possible cases of election hacking, and make policies that prohibit hacking in the future or tampering of any kind. This year it works in their favor. Next time it might work against them. That is one thing we have to come together and fix with severe penalties. But it is not something the Democratic Party can do to stop losing seats in the House and Senate, local governments, governorships, and the President.