-LRB- CNN -RRB- -- Sen. Barack Obama will take a break from campaigning Thursday so he can visit his ailing grandmother in Hawaii , an Obama spokesman said Monday . Sen. Barack Obama will take a break from campaigning so he can visit his ailing grandmother . `` Sen. Obama 's grandmother Madelyn Dunham has always been one of the most important people in his life , '' spokesman Robert Gibbs told reporters . `` In the last few weeks , her health has deteriorated to the point where her situation is very serious . It is for that reason that Sen. Obama has decided to change his schedule on Thursday and Friday so that he can see her and spend some time with her , '' Gibbs said . The interruption will cause Obama to cancel Thursday events in Madison , Wisconsin and Des Moines , Iowa . He will do an event in Indianapolis , Indiana , Thursday morning before leaving and will return to the campaign Saturday , Gibbs said . Michelle Obama will fill in for her husband on Friday at previously scheduled events in Columbus and Akron , Ohio , his campaign said . Obama speaks about his grandmother often on the stump , describing her as an integral figure in his youth who struggled against the glass ceiling in to make a better life for him . `` She 's the one who put off buying a new car or a new dress for herself so that I could have a better life , '' he said in his acceptance speech at the Democratic National Convention in August . `` She poured everything she had into me . And although she can no longer travel , I know that she 's watching tonight , and that tonight is her night as well . '' He and his family traveled to Hawaii in August to visit her . The Obama team made the announcement after a busy day of trading attacks with Sen. John McCain on the Democratic presidential hopeful 's readiness for office . Monday also marked the first time that Obama appeared with Sen. Hillary Clinton during the general election season . Clinton went to Florida , a state she won in the primary but whose delegates she could not claim , to urge her supporters to turn out for Obama on Election Day . Clinton called Orlando and central Florida `` the battleground of the battleground '' and practically begged the crowd to vote early . `` We are 15 days from the finish line and we can not falter , we can not stop , we can not take a single vote for granted , '' Clinton said Monday . `` I am asking you to work as hard for Barack as you worked for me . If you made phone calls for me , make them for Barack . If you walked streets for me , make them for Barack . If you talked to your friends and neighbors for me , do it again for Barack . We can not risk four more years of the same failed Republican policies . '' Earlier in the day , McCain told a crowd in Belton , Missouri , that the next president `` wo n't have time to get used to the office . '' He was addressing comments made Sunday by Obama 's running mate , Sen. Joe Biden , in which he said Obama would be tested within the first six months of his presidency . `` We do n't want a president who invites testing from the world at a time when our economy is in crisis and Americans are already fighting in two wars , '' McCain said . `` What is more troubling is that Sen. Biden told their campaign donors that when that crisis hits , they would have to stand with them because it would n't be apparent Sen. Obama would have the right response . The Obama-Biden campaign released a pre-emptive response after reading McCain 's scheduled remarks . `` With our nation facing two wars and 21st century threats abroad , Sen. Biden referenced the simple fact that history shows presidents face challenges from day one , '' Obama spokesman David Wade said . `` After eight years of a failed foreign policy , we need Barack Obama 's good judgment and steady leadership , not the erratic and ideological Bush-McCain approach that has set back our security and standing in the world . '' Earlier Monday , Obama denounced the `` say-anything , do-anything politics '' of McCain 's camp , but said `` careless , outrageous comments '' wo n't distract him from addressing the nation 's ills . Obama added that Alaska Gov. Sarah Palin , McCain 's running mate , rejected some of the tactics when she spoke out against a flood of automated phone calls tying Obama to former radical William Ayers . The calls were reported in several battleground states . `` It 's getting so bad that even Sen. McCain 's running mate denounced his tactics last night , '' Obama said at a campaign event in Tampa , Florida . `` As you know , you really have to work hard to violate Gov. Palin 's standards on negative campaigning . '' Sunday night , Palin told reporters traveling with her that if she had her way , the McCain campaign and the Republican National Committee would not be flooding battleground states with the automated phone calls , which she said the Obama campaign was using too . Over the next 15 days , Obama said Monday , he will continue his quest for the Oval Office while disregarding the divisive politics that he said McCain is endorsing `` to keep us from working together . '' The McCain campaign , meanwhile , continued its weekend assault on Obama 's tax plan , which it called an attempt to `` spread the wealth . '' iReport.com : Send your questions for Sen. John McCain Speaking at a campaign event in St. Charles , Missouri , a chorus of boos rang out as the Arizona senator described his take on the plan . `` He believes in redistributing wealth -- not in policies that grow our economy and create jobs and opportunities for all Americans . Sen. Obama is more interested in controlling who gets your piece of the pie than in growing the pie . '' In Colorado Springs , Colorado , Palin also continued her line of attack from the weekend , but softened her tone in that she did n't call Obama 's plan socialism . Watch Palin say Obama sounds like a socialist '' Over the weekend , Palin and Sen. Mel Martinez , a Cuban-American GOP senator from Florida , called Obama 's plan socialism . Martinez compared the plan to the tax structure in communist Cuba . McCain has taken a softer tone . On Sunday , he dodged a question from Fox News ' Chris Wallace about whether Obama was a socialist , but said his rival 's tax plan was an effort `` to spread the wealth . '' `` That 's one of the tenets of socialism , '' McCain said . Watch Obama defend his plan '' Obama 's tax plan calls for tax relief for 95 percent of workers and their families . Though nonpartisan tax policy organizations agree that 40 percent of Americans do n't pay income tax , many of those are lower-income earners who file payroll taxes through their employers . See the fact check After receiving an endorsement from Colin Powell , a former Republican secretary of state and retired Army general , Obama asked if Powell and billionaire Warren Buffett -- No. 2 on Forbes magazine 's 2008 list of richest Americans -- would have extended their backing if he was a socialist . Watch Obama explain Powell 's influence '' Obama said he simply wants to give the middle class a tax cut . Powell came to Obama 's defense after endorsing the senator from Illinois . Powell said he had grown tired of McCain 's negative campaigning and that the American people would prefer to focus on issues like education , infrastructure and the economy . He specifically slammed Palin 's allegation that Obama 's tax plan is socialist , calling it misleading . iReport.com : What do you think about Powell 's endorsement ? `` For us to say that makes you a socialist , I think , is an unfortunate characterization that is n't accurate . ''