The Labor party which was 20 percent ahead in the polls at the beginning of the electoral campaign lost the election because of Hamas suicide bombers. BArak, who was on the brink of signing a peace agreement with Arafat, was defeated because of the Second intifada, which was launched just after he finally accepted to improve the Camp David offer. As for Olmert, had he stayed in power two more months, a peace agreement would've been signed. However, thanks to Hezbollah and Hamas missile firing, Likud which ended up with only 12 seats in 2006, regained the premiership. Do the math, it's very simple: no Hamas, no Likud!
from the article: Dear Palestinian leaders, your destiny is in your own hands