With Election Day drawing near, the Democratic Congressional Campaign Committee ratcheted up its campaign ad spending significantly over the past two days, and new filings late Wednesday revealed that the committee is expanding the number of districts in which it is airing television ads.

The committee filed $6.3 million worth of independent expenditures Wednesday, bringing its total IE spending to more than $45 million. The new totals show that the DCCC now has more than $1 million invested in each of 18 races across the country.

The latest to move over the $1 million line are those involving Reps. Phil English (R-Pa.), Baron Hill (D-Ind.), Steve Chabot (R-Ohio) and Christopher Shays (R-Conn.), as well as the open-seat race in Illinois’ 11th district.

Wednesday’s filings also revealed that the DCCC is beginning to expand the battleground in terms of the number of districts where the committee is spending money. The DCCC reported new media buys targeting Reps. Shelley Moore Capito (R-W.Va.), Virgil Goode (R-Va.) and Henry Brown (R-S.C.) — all incumbents who to this point have been considered likely to win re-election. Privately, Republicans are increasingly concerned about Brown’s race, and it would be a major upset if Democrat Linda Ketner, the openly gay heir to the Food Lion supermarket fortune, were to pull off a win.

The DCCC is also now up in Oregon’s 5th district, a Democratic-held open seat that has not been considered in jeopardy of switching hands.

The committee’s IE arm also placed significant media buys in Virginia’s 2nd district and Washington’s 8th this week, where Reps. Thelma Drake (R) and Dave Reichert (R) are facing difficult re-election contests, respectively.

House Democrats also made a significant investment in Florida this week, against GOP Reps. Mario Diaz-Balart, Lincoln Diaz-Balart and Tom Feeney. The DCCC has now spent more than $500,000 against each of the Diaz-Balart brothers and close to $1 million against Feeney.

Meanwhile, as the Democrats are increasing their investments in GOP districts, this week marks the first evidence of Republican incumbents being hung out to dry by the cash-strapped National Republican Congressional Committee.

As of Wednesday, the NRCC had pulled its reserved advertising time out of Minnesota’s 6th district, where freshman Rep. Michele Bachmann (R) finds herself caught in a firestorm she set off by making controversial comments on MSNBC’s “Hardball” Friday suggesting the Democratic presidential nominee, Sen. Barack Obama (Ill.), holds anti-American views.

Republicans also appear to be writing off the re-election of Rep. Marilyn Musgrave (R-Colo.), who has been behind in virtually all recent public polling. The NRCC reported placing a significant ad buy in the 4th district this week, but a committee source confirmed late Wednesday that they were pulling out of that race as well.