At the beginning of this presidential campaign, the war in Iraq dominated the news.

Today the economy dominates the news, and a period of historic turmoil on Wall Street — with the government seeking to provide $700 billion to bail out troubled mortgage lenders, an insurance firm and an investment bank — has promised to keep the political spotlight on economic issues.

The economic planks of Democratic nominee Barack Obama and Republican nominee John McCain share some common ground, though their principal positions won’t surprise anyone familiar with the doctrines of their respective parties.

Here’s look at their economic positions, and their reactions to the dizzying recent events.

Consistent with Republican orthodoxy, McCain touts tax cuts and caps. McCain has supported President Bush’s tax cuts and favors cutting the corporate tax rate from 35 percent to 25 percent to stimulate domestic job and economic growth.

He opposes taxes on internet transactions, and earlier this year favored the ideas of a “tax holiday” suspending the federal tax on gallons of gasoline for the summer.

In policies laid out before the landscape changed this week, McCain said that through spending limits such as a one-year freeze on non-military, non-veteran federal budget growth, slashing of earmarks and other tools, that the federal government could eliminate the national debt by 2013. However, he has said the key to budget reform is in major revamps of Social Security, Medicare, and Medicaid.

Consistent with Democratic orthodoxy, Obama calls for government investment to help stimulate jobs, and seeks to strengthen the rights of workers and consumers.

Obama opposed Bush’s tax cuts, has proposed enacting a windfall tax on oil company profits, and calls for launching a $50 billion spending program to invest in roads, infrastructure and the jobs they create and a $25 billion fund for states to maintain social services in a time of cuts. Obama proposals include stricter protections against mortgage fraud and tighter controls on credit card companies.

On the federal budget, Obama has called for reinstatement of so-called Pay-Go rules requiring the government to identify a funding source before approving an expenditure, and a rollback of the tax cuts enacted during the Bush administration.

Both men support increased global trade, though Obama says recent trade deals such as CAFTA and NAFTA should be renegotiated so they are more favorable for U.S. workers. Both men encourage a slate of “green technology” stimuli. Both advocate tax law changes that would favor companies that grow their domestic labor forces, and policies in which the government would help provide stable mortgages to prevent more homeowners from slipping into foreclosure.

Both men have said they support the bailouts of the insurer AIG, lenders Fannie Mae and Freddie Mac and investment bank the Lehman Bros. Both men have offered balancing statements, asserting the bailouts present dangerous risks and should not protect those who profited while others suffer the financial consequences.

McCain this week proposed a new agency within the Treasury Department to protect against future failures. He also criticized Obama’s response to financial pressures.

“The crisis on Wall Street started in the Washington culture of lobbying and influence peddling, and he was right square in the middle of it,” said McCain.

Obama has yet to offer his own policy response to the developing problems, but stated his support for the emergency bailout powers sought by the Bush administration and Treasury Secretary Henry Paulson on Friday.

“It is critical at this point that the markets and the public have confidence that their work will be unimpeded by partisan wrangling, and that leaders in both parties work in concert to solve the problem at hand.”