Hi, Nadi. Welcome to A2K. As you may have noticed, a couple of the people that have responded to your question so far are Bush supporters, and not very well informed ones at that.
If you want to learn more, and get the facts rather than biased personal opinions, here are a few links you might want to check out.
Some information on PNAC, which is the group of highly placed Bush administration personnel that, prior to Bush's taking of our government, decided war in Iraq was needed for their own personal gain. The suggested PNAC policies are being played out in the current administration.
http://www.disinfopedia.org/wiki.phtml?title=PNAC
Kerry fought in Vietnam and upon returning to the US, was outspoken about what was wrong with the war. He said some things which other vietnam veterans became angry about, but it wasn't just about their honor. Politics played an important part, too. The leader of the current Swift Boat Veterans for Truth goes way back in the Republican Party.
http://www.disinfopedia.org/wiki.phtml?title=John_E._O'Neill
After Kerry's Anti War protesting days, he was elected to the US Senate. Fresh into politics, and with his skills as a lawyer/ prosecutor, he tackled two of the largest, most intricate scandals in US history - which by the way, also dealt with busting terrorists AND the Republican Party AND several Bush family members.
The two scandals were Iran Contra and the BCCI, the latter being a terrorist front for laundering money (including Iraq arms sales) as well as having ties to the eventual failing of Savings and Loan companies across the country. Several Bush family members were caught with their hand in the cookie jars of the Savings and Loans.
BCCI Info can be found at:
http://fas.org/irp/congress/1992_rpt/bcci/ (Note Kerry's lead role)
http://www.washingtonmonthly.com/features/2004/0409.sirota.html
Iran Contra / Bush Sr. / Kerry's role in outing the illegal arms trade: (Take your pick... There's lot's of information here)
http://websearch.cnn.com/search/search?Coll=cnn_xml&QuerySubmit=true&Page=1&source=cnn&sites=web&query=Iran+Contra
In short, Kerry has already proven that he is tough on terrorism. He broke the terrorist funding scandal 15 years ago while Bush Sr. was befriending the enemy. He does not have ties to Carlyl Group, Halliburton, oil companies or, most importantly, PNAC, all of which are close to Bush.
Now that we are in Iraq, Kerry will have to take care in making sure Iraq is rebuilt prior to withdrawing troops. There is no choice but to do so. Bush Sr. encouraged an Iraqi uprising against Saddam during the first Gulf War and promised to provide security for Iraqi's trying to overthrow Saddam. There was no protection provided and they were left to die at the hands of Saddam. Kerry will not make that mistake. He has served with honor thus far, and I am confident he will continue to do so. His history backs him up.