Adding to slaacaa's fantastic summary, "unites behind" might be a bit of a stretch; there are a miriad of ways to be in the opposition, and it's not like the US where you essentially pick from two options (maybe three, but the rest is quite insignificant), but there's like half a dozen parties opposing Fidesz, the governing party. Unfortunately, due to having vastly different approaches and opinions, these parties could never unite properly and there have always been some infighting between them, especially during elections, which doesn't really give the best impression to voters. They have tried to unite twice already and both attempts led to another 2/3 majority for Fidesz.
Now that finally there is another competitor who seems to have more support (while having about the same amount of ideas and plans for the future), these opposition parties are not all 100% supportive, further diluting votes against the current regime.
It's still slightly more hopeful than the previous times, because finally Tisza, the new party seems to have more supporters than the largest opposition party that still runs a previous, horribly failing prime minister's wife.
But saying that the opposition finally unites... Is a bit of a stretch in my opinion.
It comes in handy when you want the multiple of a number.